(a) Sequence of axisymmetric shapes of a vesicle (black) during an inflation and deflation cycle between v = 0.65 and v = 0.71, including the equilibrium location of the colloid ring (red). The rectangle refers to the region depicted in (b)–(e). (b)–(e) Different actuation protocols for the periodic change of volume as a function of time, leading to different swimming strokes. (b) Slow inflation–slow deflation induces a reciprocal stroke which does not allow for swimming; (c) slow inflation–quick deflation, (d) quick inflation–slow deflation, and (e) quick inflation–quick deflation all induce non-reciprocal strokes.