Girih are the interlaced geometric strapwork patterns of Islamic architectural decoration — star-and-polygon tessellations built from a small set of tiles that repeat without end. On a Persian mosque wall they read as lustrous cobalt-and-turquoise glazed ceramic, the interlacing drawn in gold over a white-line ground.

This is mathematized sacred ornament: lapis-lazuli ultramarine and pyrite gold, exact and seamless. The tradition is aniconic — no figures, only the infinite repeat of decagons, pentagons and radiating stars, locked together with the precision of a geometer's compass.