Lesson 12 of the 'Problems in Teaching' series in Master Weaver, on drafting variations of three-block patterns. It explains that a simple profile with one square per block yields 64 symmetrical variations for three blocks (8 for two, 1024 for four), regardless of weave structure. It shows how to build the variations from a grid (Fig. 1) and works a practical example (variation 5F) on a profile in Fig. 2. It notes that weaves producing two-sided patterns, such as summer and winter, need only 32 samples.