P156 Hans Leo hassler is a period 156 traffic light hassler discovered by Noam Elkies on January 4, 1995 and was the first period 156 oscillator to be found. It features two crowns turning a traffic light into a B-heptomino, and two eater 1s that then turn the B-heptomino back into a traffic light.
This oscillator has several simple variants, also found by Elkies, that can be acquired by altering the phase of one of the crowns. Below are period 132 and period 144 versions of the oscillators.
A period 144 version of the Hans Leo hasslerRLE: here