I've used one of the variants of this (barrier) in the past on a very low budget video wall. 3x3 array of 32"-ish monitors each attached to a raspberry pi, so

I've used one of the variants of this (barrier) in the past on a very low budget video wall. 3x3 array of 32"-ish monitors each attached to a raspberry pi, so it was extremely useful to control from a single keyboard/mouse. It's nice to see it's still going strong, and that they're making efforts to keep the forks/variants aligned.