Signals  are constructed using auxiliary signals, which propagate to the left. Every second time a signal moves (to the right), it sends an auxiliary signal to the left. moves on its own at speed 1 while each of the slower signals moves only when it gets an auxiliary signal.
Signals are created using auxiliary signals, which travel to the left. Every second time a signal moves (to the right), it sends an auxiliary signal to the left. The signals move at a speed of 1 while each of the slower signals only moves when it receives an auxiliary signal.