This is a 3D-printable puzzle made from Escher’s Plane Filling II, inspired by thing http://www.thingiverse.com/thing:966.

It is printed in three parts:

1. black animals
2. white animals
3. frame

The animal STL files are available in two versions each. One including the contours as a 0.2 mm layer on top of the surfece, the other with flat surface and a separate STL file with the contours to add-on. A separate STL for contours can be useful for dual color printing or separate print settings for the fine details of the contours.

Dual color printing can be done even with a single extruder by changing the filament at 3.2 mm height. Josef Prusa offers a tool which inserts an M600 G-Code command at a given layer height: http://www.prusaprinters.org/color-print/

Alternatively, the contours can be printed in the same color (see example photo of the dragon) or subtracted to make an engraved contour (see other example photo of the dragon). I would recommend the dual color version, though.