I’m Paul Cantrell I teach computer science here at McAllister which raises
science here at McAllister which raises
science here at McAllister which raises an interesting question why why do I
an interesting question why why do I
an interesting question why why do I teach computer science at a liberal arts
teach computer science at a liberal arts
teach computer science at a liberal arts college well the short answer to that
college well the short answer to that
college well the short answer to that question is that computer science is or
question is that computer science is or
question is that computer science is or at least can be more than just job
at least can be more than just job
at least can be more than just job training and so should education to help
training and so should education to help
training and so should education to help illustrate what I mean by that I want to
illustrate what I mean by that I want to
illustrate what I mean by that I want to talk about a project that I wrote with
talk about a project that I wrote with
talk about a project that I wrote with my excellent colleagues at bust out
my excellent colleagues at bust out
my excellent colleagues at bust out solutions for the Como Zoo and
solutions for the Como Zoo and
solutions for the Como Zoo and conservatory they wanted an interactive
conservatory they wanted an interactive
conservatory they wanted an interactive iPad exhibit to go with their bonsai
iPad exhibit to go with their bonsai
iPad exhibit to go with their bonsai tree exhibit that would let kids make
tree exhibit that would let kids make
tree exhibit that would let kids make their own virtual bonsai tree on an iPad
their own virtual bonsai tree on an iPad
their own virtual bonsai tree on an iPad keep him busy for five minutes while
keep him busy for five minutes while
keep him busy for five minutes while their parents look at the trees and
their parents look at the trees and
their parents look at the trees and hopefully maybe even educate and engage
hopefully maybe even educate and engage
hopefully maybe even educate and engage and inspire them which gave us an
and inspire them which gave us an
and inspire them which gave us an interesting problem to solve we had to
interesting problem to solve we had to
interesting problem to solve we had to create a tree in software and I don’t
create a tree in software and I don’t
create a tree in software and I don’t just mean a picture of a tree we want
just mean a picture of a tree we want
just mean a picture of a tree we want you to be able to trim your own tree
you to be able to trim your own tree
you to be able to trim your own tree your choice is your tree that means we
your choice is your tree that means we
your choice is your tree that means we need an algorithm that makes things that
need an algorithm that makes things that
need an algorithm that makes things that look and feel like trees the way we do
look and feel like trees the way we do
look and feel like trees the way we do that is using something called an L
that is using something called an L
that is using something called an L system and the way it works is we start
system and the way it works is we start
system and the way it works is we start with just one segment we’re gonna build
with just one segment we’re gonna build
with just one segment we’re gonna build tree out of these segments we start with
tree out of these segments we start with
tree out of these segments we start with a segment and we apply a rule to it
a segment and we apply a rule to it
a segment and we apply a rule to it that’s the rule at the lower left there
that’s the rule at the lower left there
that’s the rule at the lower left there take that segment and replace it with
take that segment and replace it with
take that segment and replace it with several segments and then we take each
several segments and then we take each
several segments and then we take each of these several segments and apply the
of these several segments and apply the
of these several segments and apply the same rule to them and apply the rule to
same rule to them and apply the rule to
same rule to them and apply the rule to each of these segments and we get a
each of these segments and we get a
each of these segments and we get a structure a plant like structure that we
structure a plant like structure that we
structure a plant like structure that we can work with here’s what that looks
can work with here’s what that looks
can work with here’s what that looks like on an iPad this doesn’t look like a
like on an iPad this doesn’t look like a
like on an iPad this doesn’t look like a tree yet but we’ll get there the first
tree yet but we’ll get there the first
tree yet but we’ll get there the first thing we need to do to make it look like
thing we need to do to make it look like
thing we need to do to make it look like a bonsai is that on one side trees start
a bonsai is that on one side trees start
a bonsai is that on one side trees start out dents and shrubby so that you have
out dents and shrubby so that you have
out dents and shrubby so that you have material to trim away we need to make
material to trim away we need to make
material to trim away we need to make our tree look shrubby the way I do that
our tree look shrubby the way I do that
our tree look shrubby the way I do that is at each step of the substitution I
is at each step of the substitution I
is at each step of the substitution I remove a few segments so instead of
remove a few segments so instead of
remove a few segments so instead of substitute substitute substitute it’s
substitute substitute substitute it’s
substitute substitute substitute it’s now
now
now that you remove a few substitute remove
that you remove a few substitute remove
that you remove a few substitute remove a few that kind of keeps it dense as it
a few that kind of keeps it dense as it
a few that kind of keeps it dense as it grows here’s what it looks like and it
grows here’s what it looks like and it
grows here’s what it looks like and it looks shrubby for sure but it’s like
looks shrubby for sure but it’s like
looks shrubby for sure but it’s like some kind of grassy tumbleweed maybe we
some kind of grassy tumbleweed maybe we
some kind of grassy tumbleweed maybe we want something that looks like a woody
want something that looks like a woody
want something that looks like a woody tree so how do we do that how do we make
tree so how do we do that how do we make
tree so how do we do that how do we make it look like wood well perhaps we might
it look like wood well perhaps we might
it look like wood well perhaps we might want to get an image of some bark right
want to get an image of some bark right
want to get an image of some bark right something better than this generic Brown
something better than this generic Brown
something better than this generic Brown some maybe even the texture of the bark
some maybe even the texture of the bark
some maybe even the texture of the bark but no it turns out there’s a much
but no it turns out there’s a much
but no it turns out there’s a much simpler and more effective way to make
simpler and more effective way to make
simpler and more effective way to make it look like a woody tree which is that
it look like a woody tree which is that
it look like a woody tree which is that we take each of these segments that the
we take each of these segments that the
we take each of these segments that the tree is built out of and we make them
tree is built out of and we make them
tree is built out of and we make them thicker depending on how many
thicker depending on how many
thicker depending on how many descendants they have up the tree and we
descendants they have up the tree and we
descendants they have up the tree and we make them just slightly taller if
make them just slightly taller if
make them just slightly taller if they’re closer to the root of the tree
they’re closer to the root of the tree
they’re closer to the root of the tree and there we have something that
and there we have something that
and there we have something that actually I think looks like it’s made
actually I think looks like it’s made
actually I think looks like it’s made out of wood doesn’t it it’s still just a
out of wood doesn’t it it’s still just a
out of wood doesn’t it it’s still just a bunch of cylinders stuck together
bunch of cylinders stuck together
bunch of cylinders stuck together there’s not a lot going on here but what
there’s not a lot going on here but what
there’s not a lot going on here but what turned out to be a problem of shape and
turned out to be a problem of shape and
turned out to be a problem of shape and proportion might have seemed at first
proportion might have seemed at first
proportion might have seemed at first like a problem of color and texture um
like a problem of color and texture um
like a problem of color and texture um something that happens when we write
something that happens when we write
something that happens when we write software it asks us to look at things
software it asks us to look at things
software it asks us to look at things very closely software involves close
very closely software involves close
very closely software involves close seeing and therefore software becomes a
seeing and therefore software becomes a
seeing and therefore software becomes a way of seeing like any creative endeavor
way of seeing like any creative endeavor
way of seeing like any creative endeavor software is a way of seeing the work
software is a way of seeing the work
software is a way of seeing the work we’re doing right here this is this is
we’re doing right here this is this is
we’re doing right here this is this is not scientific seeing we’re not forming
not scientific seeing we’re not forming
not scientific seeing we’re not forming a hypothesis about a tree we’re trying
a hypothesis about a tree we’re trying
a hypothesis about a tree we’re trying to do something artistic the goal is not
to do something artistic the goal is not
to do something artistic the goal is not accuracy it’s to it’s to make something
accuracy it’s to it’s to make something
accuracy it’s to it’s to make something convincing now there’s a problem with
convincing now there’s a problem with
convincing now there’s a problem with this it’s a pretty serious one you’ll
this it’s a pretty serious one you’ll
this it’s a pretty serious one you’ll see it when i zoom in the cylinders
see it when i zoom in the cylinders
see it when i zoom in the cylinders don’t quite join up in some places there
don’t quite join up in some places there
don’t quite join up in some places there are these visible seams between them
are these visible seams between them
are these visible seams between them because when you take a bunch of
because when you take a bunch of
because when you take a bunch of cylinders with their hard edges and you
cylinders with their hard edges and you
cylinders with their hard edges and you stick them together sometimes there are
stick them together sometimes there are
stick them together sometimes there are little gaps well one way to solve that
little gaps well one way to solve that
little gaps well one way to solve that might be to round off the ends right so
might be to round off the ends right so
might be to round off the ends right so let’s see what that looks like
let’s see what that looks like
let’s see what that looks like oh that’s arguably even worse
oh that’s arguably even worse
oh that’s arguably even worse to understand why this is so bad we need
to understand why this is so bad we need
to understand why this is so bad we need to know a little bit about how computers
to know a little bit about how computers
to know a little bit about how computers do shading in 3d graphics when you have
do shading in 3d graphics when you have
do shading in 3d graphics when you have a 3d model you compute what’s called the
a 3d model you compute what’s called the
a 3d model you compute what’s called the normals these are just lines that stick
normals these are just lines that stick
normals these are just lines that stick straight out from the surface then you
straight out from the surface then you
straight out from the surface then you imagine light falling on the surface and
imagine light falling on the surface and
imagine light falling on the surface and you say well if one of these normals is
you say well if one of these normals is
you say well if one of these normals is placing is is pointing straight at the
placing is is pointing straight at the
placing is is pointing straight at the light then we should give it a little
light then we should give it a little
light then we should give it a little high light and if it’s pointing more
high light and if it’s pointing more
high light and if it’s pointing more away from the light than not then we
away from the light than not then we
away from the light than not then we should put it in shadow that’s how we do
should put it in shadow that’s how we do
should put it in shadow that’s how we do shading the reason it looks so bad when
shading the reason it looks so bad when
shading the reason it looks so bad when we put two of these rounded ends next to
we put two of these rounded ends next to
we put two of these rounded ends next to each other is that when we do that we
each other is that when we do that we
each other is that when we do that we end up with normals pointing very
end up with normals pointing very
end up with normals pointing very different directions right next to each
different directions right next to each
different directions right next to each other which means that the light and the
other which means that the light and the
other which means that the light and the shadow make an abrupt transition now we
shadow make an abrupt transition now we
shadow make an abrupt transition now we might fix this by saying trying to fill
might fix this by saying trying to fill
might fix this by saying trying to fill in those little gaps but it turns out
in those little gaps but it turns out
in those little gaps but it turns out mathematically and programmatically
mathematically and programmatically
mathematically and programmatically that’s very difficult to do and there’s
that’s very difficult to do and there’s
that’s very difficult to do and there’s an easier faster better way which is
an easier faster better way which is
an easier faster better way which is that we just take these normals and he
that we just take these normals and he
that we just take these normals and he lie we straight up lie we say actually
lie we straight up lie we say actually
lie we straight up lie we say actually it’s always pointing straight off to the
it’s always pointing straight off to the
it’s always pointing straight off to the side even when it isn’t that makes it so
side even when it isn’t that makes it so
side even when it isn’t that makes it so that when there’s a joined point between
that when there’s a joined point between
that when there’s a joined point between two of these rounded edges there’s not
two of these rounded edges there’s not
two of these rounded edges there’s not such an abrupt transition and in fact
such an abrupt transition and in fact
such an abrupt transition and in fact that fixes the problem we’ve only
that fixes the problem we’ve only
that fixes the problem we’ve only changed the shading and not the shape it
changed the shading and not the shape it
changed the shading and not the shape it seemed like it was a problem of shape
seemed like it was a problem of shape
seemed like it was a problem of shape it’s really a problem of light and dark
it’s really a problem of light and dark
it’s really a problem of light and dark and shading on which is the beautiful
and shading on which is the beautiful
and shading on which is the beautiful thing about software we come up with
thing about software we come up with
thing about software we come up with ideas notions assumptions hopes wishes
ideas notions assumptions hopes wishes
ideas notions assumptions hopes wishes and dreams we encode them we literally
and dreams we encode them we literally
and dreams we encode them we literally encode them and then the computer throws
encode them and then the computer throws
encode them and then the computer throws them back at us with mindless literalism
them back at us with mindless literalism
them back at us with mindless literalism and we see our own ideas and our ideas
and we see our own ideas and our ideas
and we see our own ideas and our ideas talk back to us software makes our ideas
talk back to us software makes our ideas
talk back to us software makes our ideas talk back to us if we let it right now
talk back to us if we let it right now
talk back to us if we let it right now we need people desperately need people
we need people desperately need people
we need people desperately need people who will listen to that because software
who will listen to that because software
who will listen to that because software is doing a lot of things in our world
is doing a lot of things in our world
is doing a lot of things in our world it’s talking back to us in surprising
it’s talking back to us in surprising
it’s talking back to us in surprising ways and we need to listen to that now
ways and we need to listen to that now
ways and we need to listen to that now we throw a few leaves on that thing and
we throw a few leaves on that thing and
we throw a few leaves on that thing and you got something that looks like it
you got something that looks like it
you got something that looks like it looks like a tree right it’s pretty cool
looks like a tree right it’s pretty cool
looks like a tree right it’s pretty cool and the beautiful thing about having an
and the beautiful thing about having an
and the beautiful thing about having an algorithm for this is that if we just
algorithm for this is that if we just
algorithm for this is that if we just change the art for the leaves and tweak
change the art for the leaves and tweak
change the art for the leaves and tweak a few parameters in the algorithm we get
a few parameters in the algorithm we get
a few parameters in the algorithm we get not only an endless variety of maples
not only an endless variety of maples
not only an endless variety of maples but also junipers ficuses the only
but also junipers ficuses the only
but also junipers ficuses the only difference between these three species
difference between these three species
difference between these three species of trees is a few numbers in an
of trees is a few numbers in an
of trees is a few numbers in an algorithm and different art for the
algorithm and different art for the
algorithm and different art for the leaves what we’re doing here this is
leaves what we’re doing here this is
leaves what we’re doing here this is this is essentially art we’re making a
this is essentially art we’re making a
this is essentially art we’re making a tree drawing a tree but we’re making it
tree drawing a tree but we’re making it
tree drawing a tree but we’re making it with algorithms it’s art and the medium
with algorithms it’s art and the medium
with algorithms it’s art and the medium is algorithms you can see why software
is algorithms you can see why software
is algorithms you can see why software companies put a huge premium on people
companies put a huge premium on people
companies put a huge premium on people who can cross boundaries and synthesize
who can cross boundaries and synthesize
who can cross boundaries and synthesize ideas from different fields if we take a
ideas from different fields if we take a
ideas from different fields if we take a look at the finished app here’s somebody
look at the finished app here’s somebody
look at the finished app here’s somebody working on their tree after a few
working on their tree after a few
working on their tree after a few minutes perfecting their masterpiece
minutes perfecting their masterpiece
minutes perfecting their masterpiece here’s math software art and graphic
here’s math software art and graphic
here’s math software art and graphic design a smidge of botany also
design a smidge of botany also
design a smidge of botany also psychology if the user putting ourselves
psychology if the user putting ourselves
psychology if the user putting ourselves in the user’s shoes which is something
in the user’s shoes which is something
in the user’s shoes which is something that we get actually from reading
that we get actually from reading
that we get actually from reading literature and there’s also the many
literature and there’s also the many
literature and there’s also the many factors that went into this nonprofit
factors that went into this nonprofit
factors that went into this nonprofit their mission what do they want all
their mission what do they want all
their mission what do they want all these different disciplines are coming
these different disciplines are coming
these different disciplines are coming together just like we do in a liberal
together just like we do in a liberal
together just like we do in a liberal arts education like this one liberal
arts education like this one liberal
arts education like this one liberal arts is fantastic background for writing
arts is fantastic background for writing
arts is fantastic background for writing software but that’s not the question
software but that’s not the question
software but that’s not the question that I asked we get confused about this
that I asked we get confused about this
that I asked we get confused about this so easily we see that education is
so easily we see that education is
so easily we see that education is useful for jobs and we say well it must
useful for jobs and we say well it must
useful for jobs and we say well it must be worthwhile but that’s not enough
be worthwhile but that’s not enough
be worthwhile but that’s not enough that’s not enough I didn’t ask why is
that’s not enough I didn’t ask why is
that’s not enough I didn’t ask why is liberal arts education good for software
liberal arts education good for software
liberal arts education good for software I asked why does software belong in a
I asked why does software belong in a
I asked why does software belong in a liberal arts education there was a
liberal arts education there was a
liberal arts education there was a moment in this project when somebody
moment in this project when somebody
moment in this project when somebody asked how do we stop kids using this
asked how do we stop kids using this
asked how do we stop kids using this from taking their tree and just trimming
from taking their tree and just trimming
from taking their tree and just trimming it down to a stump I said what you don’t
it down to a stump I said what you don’t
it down to a stump I said what you don’t stop them
stop them
stop them you never a child yourself you walk up
you never a child yourself you walk up
you never a child yourself you walk up to this thing you can trim the tree
to this thing you can trim the tree
to this thing you can trim the tree what’s the first thing you’re gonna do
what’s the first thing you’re gonna do
what’s the first thing you’re gonna do and it’s true kid after kid you watch
and it’s true kid after kid you watch
and it’s true kid after kid you watch them using this thing at the Como Zoo
them using this thing at the Como Zoo
them using this thing at the Como Zoo they walk up to it and they trim it down
they walk up to it and they trim it down
they walk up to it and they trim it down to a stump and they say good I did yeah
to a stump and they say good I did yeah
to a stump and they say good I did yeah and then you can see it hit him they
and then you can see it hit him they
and then you can see it hit him they said wait
said wait
said wait nobody’s policing me I can trim my tree
nobody’s policing me I can trim my tree
nobody’s policing me I can trim my tree down to a stump if I want this is my
down to a stump if I want this is my
down to a stump if I want this is my tree and then it comes over them they
tree and then it comes over them they
tree and then it comes over them they become absorbed and they just lose
become absorbed and they just lose
become absorbed and they just lose themselves in that tree as they work on
themselves in that tree as they work on
themselves in that tree as they work on their personal masterpiece time after
their personal masterpiece time after
their personal masterpiece time after time you can watch this happen I walked
time you can watch this happen I walked
time you can watch this happen I walked in once and her two kids ain’t mommy
in once and her two kids ain’t mommy
in once and her two kids ain’t mommy mommy my tree is in the virtual
mommy my tree is in the virtual
mommy my tree is in the virtual collection it happens to adults too
collection it happens to adults too
collection it happens to adults too don’t tell and that moment that moment
don’t tell and that moment that moment
don’t tell and that moment that moment of realizing that this is my tree and
of realizing that this is my tree and
of realizing that this is my tree and I’m free to make it what I want that is
I’m free to make it what I want that is
I’m free to make it what I want that is what liberal arts education is about do
what liberal arts education is about do
what liberal arts education is about do any of you know what liberal arts
any of you know what liberal arts
any of you know what liberal arts actually means
actually means
actually means I confess I didn’t when I was a student
I confess I didn’t when I was a student
I confess I didn’t when I was a student I knew that it didn’t just mean
I knew that it didn’t just mean
I knew that it didn’t just mean politically liberal something bigger
politically liberal something bigger
politically liberal something bigger than that I thought it meant like
than that I thought it meant like
than that I thought it meant like liberal maybe all inclusive something
liberal maybe all inclusive something
liberal maybe all inclusive something something along those lines in fact know
something along those lines in fact know
something along those lines in fact know the Latin phrase that liberal arts comes
the Latin phrase that liberal arts comes
the Latin phrase that liberal arts comes from artist liberalist the Liebherr
from artist liberalist the Liebherr
from artist liberalist the Liebherr Alice here means of free people this was
Alice here means of free people this was
Alice here means of free people this was the education centuries ago that free
the education centuries ago that free
the education centuries ago that free people received as opposed to slaves
people received as opposed to slaves
people received as opposed to slaves this was the education that gave people
this was the education that gave people
this was the education that gave people the power to determine their own lives
the power to determine their own lives
the power to determine their own lives meaning and the ability to take
meaning and the ability to take
meaning and the ability to take responsibility for that power this was
responsibility for that power this was
responsibility for that power this was the education that people deserved and
the education that people deserved and
the education that people deserved and needed who weren’t completely defined as
needed who weren’t completely defined as
needed who weren’t completely defined as people by their economic value think
people by their economic value think
people by their economic value think about what it means that we think that
about what it means that we think that
about what it means that we think that liberal arts education is something
liberal arts education is something
liberal arts education is something narrow and specialized that only a few
narrow and specialized that only a few
narrow and specialized that only a few people need to bother with think about
people need to bother with think about
people need to bother with think about what that means this is something that
what that means this is something that
what that means this is something that every human being should have I don’t
every human being should have I don’t
every human being should have I don’t mean that everyone should go to a
mean that everyone should go to a
mean that everyone should go to a four-year private liberal arts
four-year private liberal arts
four-year private liberal arts I don’t mean that this needs to happen
I don’t mean that this needs to happen
I don’t mean that this needs to happen in school at all education is much
in school at all education is much
in school at all education is much bigger than school but this is something
bigger than school but this is something
bigger than school but this is something that every human being deserves and I
that every human being deserves and I
that every human being deserves and I don’t mean to shortchange job training
don’t mean to shortchange job training
don’t mean to shortchange job training it’s important it’s necessary but it is
it’s important it’s necessary but it is
it’s important it’s necessary but it is not sufficient we need education to be
not sufficient we need education to be
not sufficient we need education to be more than that yes we should help
more than that yes we should help
more than that yes we should help students answer the question how will I
students answer the question how will I
students answer the question how will I make money but we should also help them
make money but we should also help them
make money but we should also help them answer the question what should I do
answer the question what should I do
answer the question what should I do with that money when I have it what do I
with that money when I have it what do I
with that money when I have it what do I value what change do I want to create in
value what change do I want to create in
value what change do I want to create in the world I can trim my life to a stump
the world I can trim my life to a stump
the world I can trim my life to a stump so who do I want to be and software
so who do I want to be and software
so who do I want to be and software software can help answer these questions
software can help answer these questions
software can help answer these questions it asks us to see closely
it asks us to see closely
it asks us to see closely it makes our ideas talk back to us it
it makes our ideas talk back to us it
it makes our ideas talk back to us it shows us that everything is connected to
shows us that everything is connected to
shows us that everything is connected to everything software is kind of an ideal
everything software is kind of an ideal
everything software is kind of an ideal liberal art probably any discipline can
liberal art probably any discipline can
liberal art probably any discipline can be liberal arts is not about what we
be liberal arts is not about what we
be liberal arts is not about what we teach but about how we teach that we
teach but about how we teach that we
teach but about how we teach that we teach with the belief that every human
teach with the belief that every human
teach with the belief that every human being deserves to be the author of their
being deserves to be the author of their
being deserves to be the author of their own life’s meaning and needs to be able
own life’s meaning and needs to be able
own life’s meaning and needs to be able to take responsibility for that power
to take responsibility for that power
to take responsibility for that power that’s what liberal arts education is
that’s what liberal arts education is
that’s what liberal arts education is now I don’t know what software will look
now I don’t know what software will look
now I don’t know what software will look like in 20 or 40 years job training has
like in 20 or 40 years job training has
like in 20 or 40 years job training has kind of a short shelf life but I do know
kind of a short shelf life but I do know
kind of a short shelf life but I do know that the things that my students learn
that the things that my students learn
that the things that my students learn from writing software will serve their
from writing software will serve their
from writing software will serve their unforce evil lives in unforeseen ways
unforce evil lives in unforeseen ways
unforce evil lives in unforeseen ways and that is why I choose to spend my
and that is why I choose to spend my
and that is why I choose to spend my life teaching computer science at a
life teaching computer science at a
life teaching computer science at a liberal arts college
”
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