From Latin tessella 'small mosaic tile,' diminutive of tessera 'square,' the art of fitting shapes together without gaps.
An arrangement of shapes closely fitted together in a repeated pattern without gaps or overlapping, as in a mosaic.
From Latin tessellātus 'made of small square stones,' from tessella 'small square stone for mosaic,' diminutive of tessera 'a square tablet, die,' possibly from Greek tessares 'four' (because of the four-sided shape). Roman mosaicists used tesserae—small cubes of stone or glass—to create elaborate floor and wall designs. Key roots: *kʷetwóres (Proto-Indo-European: "four").
M.C. Escher became obsessed with tessellations after visiting the Alhambra in 1936, where Islamic artisans had explored all 17 possible plane symmetry groups centuries before mathematicians classified them. Only three regular polygons—triangles, squares, and hexagons—tessellate on their own.