Previous chapters have discussed perceptual patterns, such as subitized patterns (Chapter 2); patterns in the number words of counting (Wu, 2007, see also Chapter 3); "one-more" pattern of counting (Chapter 3), which also connects counting with arithmetic, numerical patterns (see Chapters 2, 3, 5, and 6); arithmetic patterns (see Chapter 6, as well as other examples in Parker & Baldridge, 2004); and spatial patterns (Chapters 8 and 9), including array structures (Chapter 11). Noteworthy is that none of these are examples of the typical early childhood practice of patterning—repeated sequential patterns. However, they all reflect Lynne Steen's definition of mathematics as the "science of patterns"; that is, patterns in number and space (1988). The theory of mathematics, according to Steen, is built on relations among patterns and on applications derived from the fit between pattern and observations.