Peggy’s grasp of what she could do with this micro-world has been delightfully piece meal. The first and most striking thing was learning to make the blocks walk. I seem to recall this happened in the first session. The next discovery was the BACK command. It was a discovery in the sense of being discriminated from others and producing a regular consequence from its execution. What made it her discovery ? No one else had imagined the effect of using BACK when a block was WALKing (the block hops backward in its forward path). Peggy discovered this in P170 (online). The next discrimination, a consequence of direct instruction in response to a question from her was how to select a new object of commands. I recall asking Peggy is she could make blocks other than the black (the default object) move. She was sad and said, “No.” I flatly asserted that SHE could and she asked me to show her how. I did so. (This was the Saturday before P171, I believe.) On the date of this note, Peggy changed the object she was commanding. I asked if she had [done] so on purpose or by accident. Peggy responded by changing the object of command to a different one, then smiled at me. Her turning command control may not yet be perfect (right from left) but she does discriminate between the turning commands and the others.