Coding Challenge - How much can you squeeze out of "Fifteen Lines of Code"

As a teacher I am always trying to give my younger school pupils small code examples to work from. For fun I sometimes give them fifteen lines to "play" with.

So a challenge - how much animated interactive functionality can you get out of fifteen "uncluttered" lines?

For example;
```javascript
function setup() {
createCanvas(600, 600);
}

function draw() {
translate(width/2, height/2);
for (i = 1; i <= 25; i++) {
for (j = 1; j <= 10; j++) {
rect (j*10, 0, i*j, i*j);
fill (i*10, j*25, random(mouseX/2), mouseY/2);
strokeWeight(j);
rotate (frameCount/(mouseX*10));
}
}
}
```