Algodoo

The green bug follows and catches the dots while the red one avoids them. Watch them run!
occasionally the green bug will manage to zombify the red one and it will spin in a circle. It is interesting to see the kinds of disabilities that can occur to the red one when it is half-eaten. I am so proud of these creatures!
These creatures are so simple, but elegant. The creatures don't have much for a brain and use the same thruster-turning mechanism as before. when the green creature's left antenna is touched, it immediately turns toward the food because of a spring. the spring, when pushed down, rotates the left wheel clockwise to point the wheel's thruster up, which produces a counter-clockwise torque, rotating the bug to the food.
the thrusters are inverted on the red creature, making it steer away from food. The red bug is a little smarter, because when it hits the perimeter, it immediately turns away.