Mefferts pyraminx duo puzzle – Object: Mix up the cube and put it back to the start. The Pyraminx Duo is based on an idea by Rob Stegmann. Rob’s pyraminx-like puzzle concept had only corners and centers, but no edges and it came to the attention of Oskar van Deventer. Oskar developed a prototype of the puzzle, which is now produced as Pyraminx Duo.Pyraminx Duo is arguably the easiest non-trivial twisty puzzle. It can always be solved in four moves when it has plain stickers, and in seven moves with oriented stickers. The puzzles limited difficulty, combined with its attractive look and high fiddle factor, makes it a perfect puzzle gift, also to beginners.