Non-Polycube Rep-8 Tiles
Non-polycube 3D rep-8 tiles with connected interior. All shapes except tetrahedrons are found using IFStile.
- Computer geometry: Rep-tiles with a hole (by Christoph Bandt and Dmitry Mekhontsev) 
- Hill tetrahedron 
- Anwei Liu and Barry Joe, On the shape of tetrahedra from bisection, Mathematics of Computation 63 No. 207 (2013) 141-154.