This a great little puzzle by Mineyuki Uyematsu that I saw on Puzzle Will Be Played last week. http://puzzlewillbeplayed.com/444/CubeLibre/ It's another great example of a printable puzzle that requires no support on RepRap printers. These 10 puzzle pieces can make both an 8x8 square and a 4x4x4 cube. I designed a special box in Tinkercad that allows the puzzler to play both games. https://tinkercad.com/things/8Jzfov4OYUA

Print one complete set of ten puzzle pieces (there are 4 of piece A, 4 of piece B and 2 of piece C). Neither problem is easy; there is only one solution in each case. Optionally, print the box/tray to keep them in and demonstrate the solution. The pyramid-shaped box has a cube-shaped hole in the top and a square tray on the bottom. The box can be printed without support if your reprap prints bridges nicely. If not, you might prefer to try printing the box with support turned on. A really lovely double challenge.