i’m no bobby fischer
to put that in perspective, there are over half a trillion ( 15!/2 = 653,837,184,000 )
possible permutations and half of all starting points are not solvable no matter how many permutations are tried! according to wikipedia he demonstrated his 15 puzzle prowess in 1972 on the tonight show, though sadly i can’t find a video.
we’ve had this think fun fifteen puzzle for years and it has been played with so many times by odin and us that the pieces feel smooth and well worn ( in a good way ). it’s just 2”x2” but weighs 3 oz and feels substantial and not chintzy in your hand.