Figures 1-11 are synthetic textures; adaptations of digital images. Some have been used as benchmarks in image processing papers Heeger and Bergen (1995); Simoncelli and Portilla (1998). In fact, Mao and Brown obtained some of the textures (Figures 1, 2, 3, 4, 7, and 11 ) directly from Heeger, who teaches an image processing class at Stanford (http://www.stanford.edu/class/psych267/). Mao and Brown's final project for that class Mao and Brown (1998) used all of Heeger's textures, as well as Figures 5 and 6, which were generated by Brown. Figures 8 and 9 are ``mask'' functions, used to solve interpolation problems with missing data. A detailed theoretical discussion of missing data problems and the use of masks in general is Claerbout (1998), while a direct use of these masks is Brown (1999).