3-D Escher.
Make your own topographically impossible objects using a z-printer. Link...
https://www.neatorama.com/2005/08/18/3-d-escher/Make your own topographically impossible objects using a z-printer. Link...
https://www.neatorama.com/2005/08/18/3-d-escher/Make your own Matrix text. Link...
https://www.neatorama.com/2005/08/18/matrix-text-effect/