Obviously what this world needs is MORE tetromino designs. This includes 2 different sizes, including some [potentially] baby safe 40mm version. No guarantees on that though. Kids will be kids. There's even a holder for the smaller 10mm design that holds a "complete set" of 2 of each design. See the picture or this link for details: http://en.wikipedia.org/wiki/Tetromino#Tiling_the_rectangle_and_filling_the_box_with_2D_pieces. See time-lapses of the things I print here: https://www.youtube.com/channel/UCQ9nW8XQAPWKGGKRd9LFQNQ