wouldn't it be nice if all "small-lego" bricks were available in duplo size..? ;-) this one at least makes for a nice duplo-brio connector for double-height bridges. layer 1: two thick + one thin duplo brick layer 2: five thick duplo bricks + printed flat brick layer 3: eight thick duplo bricks, top one ideally with 3.6mm nibbles (newer bricks seem to use 4.6mm ones?) not sure why this seems to fit so well, but whatever. compatible with these: http://www.thingiverse.com/thing:43278