The Ball and Spring Toy applies Verlet integration and Gauss-Seidel Relaxation to bodies made up of balls connected by springs and sticks. The bodies fall under gravity and you can apply a random impulse to them to see how they react The types of bodies available are chains of length 2, 3, and 4; wheels of size 4, 5, and 6; and a ragdoll robot. For each body type except the ragdoll robot you are given two bodies, one with springs and one with sticks. The screenshot below shows a pair of wheels of size 5 (that is, they have 5 balls on their circumferences). The one on the left is made with springs, which is shown deformed after the application of an impulse. The one on the right is made up of sticks and does not deform under impulse. The ragdoll robot has some primitive AI that attempts to make it stand up and move to the center of the window.

Keyboard Controls

Key	Action
F1	Help (this document)
Backspace	Restart with the current body type
Enter	Advance to the next body type
Space	Apply a random impulse
PrtScr (hold down)	Save screenshot to a PNG file

The LARC Engine

This code uses the LARC Engine and is part of the LARC Code Base.