Is it ensure, insure, or assure?
1690s, from Late Latin tessellatus "made of small square stones or tiles," from tessella "small square stone or tile," diminutive of tessera "a cube or square of stone or wood," perhaps from Greek tessera, neuter of tesseres, Ionic variant of tessares "four" (see four), in reference to four corners. Related: Tessellate (1826, adj.; 1791, v.; 1909, n.); tessellating.
tessellated tes·sel·lat·ed (těs'ə-lā'tĭd)
Composed of or patterned in small squares.