The role of block building in children's learning was studied by a student teacher who observed a teacher's block building curriculum in a combined first and second grade class. The purpose was to clarify the linkage between thinking and doing, spoken intention and actual consequences, and planning and spontaneity in the curriculum. The cycle of observation, reflection, and provisioning was a feature of the teacher's learning process and a significant feature of her curriculum. ("Provisioning" is described as "implementing curriculum [the teacher] feels best addresses and extends the interests and learning of the children.") The teacher observed students' interests; confirmed them upon reflection; and related them to her curriculum development by provisioning the classroom with materials that matched the children's interest. Dominant motifs in this cycle were personal meaning, integration, and continuity. Each of these resulted from the teacher's background and beliefs. The physical context of the block corner and block building became a focus of the approach to curriculum development. Block building was shown to be a rich medium for learning and social negotiation. A list of types of learning that block building enables (for example, math concepts, science, symbolization, problem solving, and art) is appended. Contains 15 references. (LB)