Hanayama Cast Vortex, designed by Akio Yamamoto, is an extremely challenging puzzle featuring three interlocking spiral (vortex) pieces. The puzzle forms a unified flat object when assembled, requiring complex three-dimensional manipulation to disassemble. With a difficulty rating of 6/6, it is one of the most challenging puzzles available. No solution is included, adding to the challenge of both disassembling and reassembling.