These Duplo train track compatible elements allow you to build bridges and ramps which are only limited by your supply of plastic! You need one bottom and one top element per slope. The middle element can be repeated to increase the size of your structure. The base of each part fits onto regular Duplo bricks (or their clones: http://www.thingiverse.com/thing:116411). All parts have an internal support structure, which facilitates printing without additional supporting materials. If you print these parts, please post pictures of the largest or tallest structure you have built with them.