Duomo, Ravenna

• The symmetry group of the tiling is *2222 (pmm).
• All the internal angles of the constituent polygons are a multiple of 15°.
• Contains one equilateral triangle.
• Contains two squares.
• There are two non-regular reflective tiles.
• The tiling satisfies the two-colour condition.
• The tiling is not edge-to-edge.
• As drawn, contains about 531 polygons.

1. Page 118 (bottom right) (Duomo, Ravenna,Italy. Marble floor mosaic, 5th-18th centuries) of F M Hessemer. Historic Designs and Patterns in Color, Dover, a1840. ISBN 048626425. [hessemer] {This collection is unusual in giving the source for almost all the patterns.} Available on Internet.

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