Figure 1: BodyBound in simulation. (a) Task schematics show six families and their intervened
body parameters. (b) Paired comparisons change the physical body with its matching description,
or the description alone. (c) Policies act from public observations, goals, and body descriptions;
fresh observations close the loop, while an independent checker evaluates measured traces. HPT
and Diffusion Policy use RGB, not depth. (d) Familiar starts, expert executions, and unchanged-
command replay separate task competence, attainability, and shared solutions. Scene geometry
stays fixed within each pair.