https://www.youtube.com/watch?v=1_1ngANuVYs SV2 means "Square-o, Version 2." Version 1 was a simple square wave oscillator built using 1/6 of an SN74HC14N Hex Schmitt Trigger. Version 2 is very much the same idea, but the dimensions are intended to comply (I think, anyway) with Intellijel/Doepfer Eurorack design specifications. This version also features vertical, mounted audio jacks and potentiometer. This is an experimental work-in-progress by an amateur, so please proceed with caution and a forgiving spirit. See more information on my project site: https://sites.google.com/view/squareov2