Early Geometrical Thinking in the Environment of Patterns, Mosaics and Isometries Read from page 22 to page 45. (Section 3.4 and 4).
Swoboda, E., & Vighi, P. (2016). Early Geometrical Thinking in the Environment of Patterns, Mosaics and Isometries (ICME-13 Topical Surveys). Cham: Springer International Publishing. Open Access (CC BY-SA 4.0)