Mini D

Warmup

Every square in this animation has a side length of 0.8. The function ptinsquare :: Point -> Point -> Boolean returns true when the first point is inside a square of side length 0.8 centered at the second point.

Animation

Outline squares are arranged in a rectangular pattern, like this:

 XXXXXXXXXX
 X        X
 X        X
 X        X
 XXXXXXXXXX

• Clicking on a square turns it blue.
• In “erase mode”, moving the mouse over a square makes it disappear.
• Hitting E enters and exits “erase mode”
• Randomly select one square on the bottom to be orange instead of blue.
• Hitting R re-randomizes that selection.