4-Arms Machine.
Move the mouse over the Machine or Torus.
The configuration space of the 4-arms machine is homeomorphic to a torus constructed from 16 squares(notice that opposite sides of the big square are identified). To each position of the central joint in which no arm is streched, there coresponds 24=16 states (each joint can take 2 positions), one state for each square. Learn more about the 4-arms machine
