Discrete sides are shown in red and blue for clarity. a, A system of check valves and switch valves within the soft controller regulates fluid flow into and through the system. The letters of ‘VERITAS’, each with a height of 500 μm, are patterned into the soft controller as an indication of scale. b, A schematic (top) and qualitative electrical analogy (bottom) of the octobot system; check valves, fuel tanks, oscillator, reaction chambers, actuators and vent orifices are akin to diodes, supply capacitors, electrical oscillator, amplifiers, capacitors and pull-down resistors, respectively. c, Conceptual curves show key variables as a function of time. (1) Nominal pressure drives fuel through system at a decreasing rate. (2) Pinch valves in the oscillator convert upstream flow into alternating flow between red and blue channels. Flow rate and switching frequency are functions of upstream pressure and downstream impedance. (3) When upstream pressure is too low, oscillation is not possible, so both sides flow at a reduced rate. (4) Catalyst decomposes fuel, yielding pressurized gas, which flows downstream to the actuators and the vent orifices concurrently. (5) Actuators deform (θ, actuator tip angle) as the pressure changes. Vents must be sufficiently small to allow full actuation, yet sufficiently large to allow timely venting.