Helical wave. 3D overlap of flagellar configurations (thin grey lines) and the trajectory of the first point in the direction of swimming (thick coloured line) over the time interval of |$1$|s, from |$9$| to |$10$|s, on the left. Corresponding f-curve traced by the first point on the |$yz$|-plane, on the right. Cases are: No Ca (top), Ca asym A & B (centre), and Ca asym A (bottom). Note that the head trace shifts upwards in z and to the right in y as time progresses.