Floor portals

Features
• Any orientation ~ upright walls or flat on the floor / ceiling
• Proper portal linking ~ return through a portal and you’ll come back to the same one you used
• Works with vanilla Nether travel (no extra items or rituals)

How to use

1. Leave the interior empty (air).
2. Light the inside with flint and steel.
3. Walk through same as a normal Nether portal.

Minimum size can be as small as a 1×1 opening (four obsidian around one portal block). Maximum interior size matches vanilla’s large-portal limit (up to 21×21 / 441 blocks).