OpenForge Wyloch/True Tile-style Dungeon Stone Tiles

This is (the start of) my take on remixing Devon Jones's classic dungeon stone tiles into the True Tiles / Wyloch format (tops only). Just an experiment at the moment.

These seem to be the most important properties:

• 1mm thick base for top of tile.
• 31.75mm squares (63.5mm for two).
• ~12.7mm total height.