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Remember the three steps [br]of making an animation?

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We start out by making some variables[br]outside the draw loop,

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and then inside the draw loop[br]we use those variables

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in our drawing code.

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So we've got a variable [br]for the <i>x</i> position,

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one for the <i>y</i> position, [br]one for the ballWidth,

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and one for the ballHeight.

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And then, at the very end,

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we change those variables [br]a little bit every time,

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so <i>x</i> is going to be [br]the old value of <i>x</i>, plus 1,

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so it's going to be increasing every time;

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<i>y</i> is going be the old value of <i>y</i>, minus 2,

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so <i>y</i> will be decreasing every time;

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ballWidth is going to get the old value[br]of ballWidth times 0.99.

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So since 0.99 is less than 1, [br]we're going to see ballWidth decreasing.

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And ballHeight is going to be[br]the old value of ballHeight

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divided by 1.01, which is greater than 1,

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and so we're also going to see [br]ballHeight decreasing.

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So if I press <i>Restart</i>, you can see

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all of these attributes [br]of the ball changing.

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So if you look at [br]these four lines of code,

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you'll notice that [br]they all follow a similar pattern.

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We've got a variable, [br]then an equals sign,

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then the same variable, some operator --[br]plus, minus, times, divide --

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and some number, okay?

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And this pattern is so common [br]in programming,

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and programmers are so lazy,[br]that they decided,

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"Hey! Since we use this pattern so much,

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"Shouldn't there be [br]an easier way to type it?"

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And so they made a shortcut, [br]and the shortcut goes like this:

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Instead of saying "x gets x plus 1",

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I could say "x plus equals 1." Got it?

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And instead of saying <i>y</i> gets <i>y</i> minus 2,[br]I could say "y minus equals 2."

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And instead of saying [br]ballWidth gets ballWidth times 0.99,

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I can say -- you guessed it --[br]<i>"ballWidth times equals 0.99"</i>

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Finally, instead of saying

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ballHeight gets ballHeight divided by 1.01

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we can say [br]<i>"ballHeight divides equals 1.01."</i>

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So for all of these, what it does is

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it takes the value of the variables,

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so ballWidth, and then this operator,

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and then multiplies it by 0.99.

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So it's going to say, [br]<i>"ballWidth times 0.99"</i>

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and then store it back [br]in the variable, ballWidth.

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And if I press <i>Restart</i> you can see

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our animation looks the same as before.

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And now you get to be lazy too!