Patented in America in 1975, the somewhat swirled pieces of this puzzle by Eldon Vaughn must be disjoined and then put back together.

The 1975 puzzle was licensed for the Cast Puzzle series. It is, without a doubt, among the most difficult of all puzzles.

"The key word is 'twist.' Don’t use too much force… the pieces should just slide apart." – Nob Yoshigahara, 2004