Simple Rube Goldberg Machine with Some Dominos

This is a simple Rube Goldberg Machine with some objects interacting with each other. I built it with different basic geometric objects like cubes, spheres, and planes. In this demo, a cube pushes a yellow ball to trigger series of dominos, one of whose branch releases a box of balls, and the other branch keeps on pushing down larger and larger dominos.I found that objects that are not physically connected (i.e., having any joint parts) can still be considered as a rigid body, which motivates me...