In the 1980's I solved the 3x3, 4x4, pyraminx, megaminx, all without any help, although it was hard. There were, however, two puzzles I was unable to solve without help, the first was square-1, which I could solve to the point of the entire cube solved except having 2 edge pieces swapped, and rubik's magic, which I actually was not really even close to solving without help.