3x3 tiles, after spending probably days on I gave up
a few years later I wrote some code to brute-force the solution, there were a total of two solutions out of ~20 billion possibilities (not including rotations)
and the box said "for kids ages 8+"...
I suspect the designers just drew it out and cut it up without realising quite how hard it was (NP complete)
https://i.etsystatic.com/17381496/r/il/440b0d/3124003935/il_...
3x3 tiles, after spending probably days on I gave up
a few years later I wrote some code to brute-force the solution, there were a total of two solutions out of ~20 billion possibilities (not including rotations)
and the box said "for kids ages 8+"...
I suspect the designers just drew it out and cut it up without realising quite how hard it was (NP complete)