CopyCat does look interesting. I note that:

"Since the 1995 FARG book, work on Copycat-like models has continued: as of 2008 the latest models are Phaeaco (a Bongard problem solver), SeqSee (number sequence extrapolation), George (geometric exploration), and Musicat (a melodic expectation model)."

3D Zendo is basically a variant on Bongard problems, and if a program can extrapolate numbers, then it could also test them against the human oracle to see if it's right.