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Allison:Hey guys!

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I was just testing out
the game I made.

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It's super easy to make simple
games like this.

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And, in fact, I'll show you
how I made it right now.

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Let's head on over to
www.scratch.mit.edu.

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We want to create a new project, so
lets click on the Create tab.

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I've already got a product opened, so
we're going to switch over here.

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>> Let's start with a quick tour
of the scratch environment.

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On the bottom left here, we have
all the sprites that will

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be used in our game.

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For example, we have a monkey,
banana, and broccoli.

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When we click on each sprite you'll
notice that the right column will

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change, to show us that we're working
with that specific sprite.

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Anything we put in this column will
control the sprite that's highlighted.

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Here in the middle, we have our column
containing our pallet a puzzle pieces,

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which we'll use to create our game.

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At the top, we have the category of
puzzle pieces we have to work with.

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For example, the blue pieces, under
the Motion tab, will allow us to

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control how our sprites move.

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We'll explore the other categories
as we create our game.

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Finally, on the top left, we
have our stage, where we'll

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actually play our game.

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Where we can see the effects of
our scripts on the sprites.

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>> So let's get started.

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In our game, the monkey will
try to eat the banana while

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avoiding the broccoli.

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The monkey will follow our mouse, and
the broccoli and banana will float

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around the stage randomly.

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When the monkey gets close to the
banana, the banana will actively try

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to avoid the monkey, just to make
things a bit more exciting.

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>> Let's start by scripting the behavior
of our main character, the monkey.

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To start our script, we'll use the When
Green Flag clicked piece from the

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events category.

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Here.

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This will cause all puzzle pieces
connected to the button to run when we

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click the Green Flag, here, at
the top right of the stage.

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We want the monkey to
follow the mouse.

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So we choose the Go To button and
select Mouse Pointer, like so.

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So we're going to try it here.

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Let's test is and see what happens.

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>> So it seems like the monkey really only
followed the first mouse click.

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This is because, by default, the
Go To block only executes once.

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To get the monkey to follow the mouse
throughout the entire game, we need

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this block to execute
over and over again.

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Sounds like we need some kind
of looping construct.

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So lets move into Control.

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Look, let's try this Forever loop.

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Seems like it works.

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>> So, next we should think about
how the monkey will

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interact with other sprites.

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Basically, we need to add logic to our
game, such that, the game will end if

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the monkey touches the banana
or the broccoli.

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And actually use the word "if"
when describing the behavior

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we're trying to create.

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And conveniently enough, there's a
control blocked called If that we use

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for exactly this purpose.

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So the diamond shape, right here, on
the block, is where we put the

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condition that we want to check.

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In this case, we'll check whether the
monkey is touching the banana.

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>> Se we grab the Touching piece
from the Sensing category.

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And choose Banana from
the drop down menu.

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Now we have to tell our sprite what
to do when it touches the banana.

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We want the game to end, and the
monkey to say, you've won.

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So we add in a Say and Stop All piece.

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We'll change, hello, to, you won.

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And the time to 0.5.

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Now, we'll apply the same logic when the
monkey is touching the broccoli,

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except we'll have the monkey say,
you lost, instead of, you won.

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>> Let's test this out and
see if it works.

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Awesome.

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We've finished scripting the monkey's
behavior, but we're not done yet.

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We still have to tell the broccoli
and banana what to do.

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>> Let's start with the simpler
of the two, the broccoli.

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Which just needs to move randomly.

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Again, we'll begin with the When
Green Flag clicked piece.

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We need the sprite to be in constant
motion, so let's drag

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out the Forever loop.

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We'll create a random motion using
some motion pieces with a random

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number generator.

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>> Alright, let's test this out.

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Awesome

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>> OK, now only the banana is left.

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Let's start off with the same
set of pieces as before.

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So if the monkey gets close,
the banana should avoid it.

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Else, the banana should move randomly.

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Sounds like a job for
this If Else block.

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In the condition, we will check the
bananas distance from the monkey, and

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then have it avoid accordingly.

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>> Now, when this condition
doesn't apply, the

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banana should move randomly.

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So let's just steal our random motion
pieces from the broccoli.

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All we have to do is drag the pieces
we want to the banana sprite, and

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they'll be copied over.

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>> All done.

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Let's test it out.

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Awesome.

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Everything seems to be working.

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Now go and make your own games.

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>> If you need some inspiration
check out past projects

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from CS50 on the website.

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>> My name is Allison, and this CS50.

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>> I need to get these set up super quick.

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