This is a CMOS 555 timer. The switches at the top are the pins. For some reason, when run too fast, it seems to get stuck in equilibrium in the high state. Only once slowed down does the simulator realize it’s unstable equilibrium. As you can see, I started to run out of room once I got to the right side of the schematic. The one pin (switch) that’s unconnected (other than the output pin) is the control pin. Wikipedia even said that one particular design of CMOS 555 timer (possibly this one) didn’t need a capacitor at the control pin and that it could be left unconnected.
