The Incredible Proof Machine (2016)

I wish I'd have had stuff like this when I was studying logic. It would sure make learning the subject more interesting especially if one's not a born logician (wading through reams of logic can get a bit tedious).

A proof machine I find incredible is no proof machine at all, but just an assertion machine.

I found the combinators in the "Simply typed lambda calculus" section a nice touch...

On iPad, I can’t drag logic blocks out of the corral on the left into the working area.