Definition to := TotalAction act_f_1 act_f_morph.Definition coin0 (sc : col_squares) : colors := sc c0.Definition coin1 (sc : col_squares) : colors := sc c1.Definition coin2 (sc : col_squares) : colors := sc c2.Definition coin3 (sc : col_squares) : colors := sc c3.

Lemma r2_inv : r2^-1 = r2.