What is this: what you see here is interactive visualization of the algorithm, which simulates "if enough signals in, then as many signals out as possible" (with certain additional features). Two more colorful greens indicate that a node has just been activated or that there is some output delay left, light green indicates that a node is about to output a signal and red indicates that node is in a cooldown mode meaning that incoming signals won't be noticed for a moment. Try this: click or touch all of the outermost nodes once and let process advance until nothing seems to happen.