Colour symmetry. Portuguese pavements: Adro da Igreja do Senhor Bom Jesus de Matosinhos (Igreja Matriz) - p2gg - «p2mg»

Small circles mean rotations of order 2. Mirrors are represented by red lines, glide reflections by green lines. Yellow lines are the border of a fundamental region. (12) means that the colours white and grey are interchanged; i means the identity.

This is an example of the case stated in the fourth row of the table in Section 4.5 (Figure 13, «p2mg») in

Periodical plane puzzles with numbers

See:
Wallpaper groups. Portuguese pavements: Adro da Igreja do Senhor Bom Jesus de Matosinhos (Igreja Matriz) - p2gg
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