Critter

Start with a simple critter.

Make a variable called critter with x and y parts.

Draw a dot to show it.

Make the critter move

make a move function to change the critter x and y.

Make a draw function to clear the screen and draw the critter at the new position.

make a wrap-around world

set a world width and a world height

if the critter is past the left edge (x<0) move it to the right edge

if the critter is past the right edge (x>worldWidth) move it to the left edge

if the critter is past the top edge (y<0) move it to the bottom edge

if the critter is past the bottom edge (y>worldHeight) move it to the top edge

give the critter some direction

add dx and dy parts to the critter

instead of adding fixed amounts to the critter position each time add the dx and dy values

change the dx and dy values a little bit each time it moves.

Make more critters

We'll make several critters with individual names

make a function to move a single critter

make a function to draw a single critter

use the functions to draw each critter in turn.

put the critters in a list.

instead of moving and drawing critters by name, make a list of critters

make a variable called allCritters to hold a list of critters

use allCritters.each() to call the move and draw functions for every critter

Now let's try making some CleverCritters