If anyone wants to try Set out with their kids, I made a free[0] Android version a while back. It's called Pipster[1] and it uses dog/cat/rabbit pictures instead of abstract shapes. "Beginner" difficulty is 3 dimensions (shape/color/number of stripes) which is much more appropriate for young children; "normal" and higher difficulties add color-of-stripes as the fourth dimension, which is equivalent to the normal Set game.
0: no ads or anything, this was a "teach myself android" project 1: https://play.google.com/store/apps/details?id=com.bogus.trio