See also the *new version*!    • Blocky Knot Portal v2  

A knot portal made of blocks.

You get back to the same place when you make three (small) loops around the portal frame. As a consequence, there are actually 24 rooms, and 4 knots.

The idea of a knot portal is not new -- you can play the beatiful KnotPortal by Moritz Sümmermann, based on the idea of Bill Thurston:

https://imaginary.org/program/knotportal

although the algorithms we have used here seem to be significantly different from KnotPortal.

Twitter thread:   / 1362426573517955074  

Source code: https://github.com/zenorogue/hyperrog...
A playable Windows exe at roguetemple.com/z/sims/notknot.zip (a bit buggy, don't go into the walls; works in VR too!)