When I was a kid in the 1950s we had some relays in the house. With the power supply from the train set I invented bistable circuits and buzzers and big wobblin

When I was a kid in the 1950s we had some relays in the house. With the power supply from the train set I invented bistable circuits and buzzers and big wobbling structures just by messing around. I also got hold of a light sensitive resistor. I invented an emergency light (came on when lights went off). Went to show it to my mum and dad, switched off the light (it was dark) but accidentally left my light pointing at the resistor. The rapid flashing was impressive and disorienting. I invented the strobe.