Video S2. Locomotion of a six-armed individual of the brittle star <i>Ophiactis brachyaspis</i>. from A general model of locomotion of brittle stars with a variable number of arms WakitaDaiki KagayaKatsushi AonumaHitoshi 2019 Resultant values are schematized in row 1 of column 1 (black circle symbol) in Fig. S2.