A display comprises a plurality of autonomous pixels on a substrate. Each autonomous pixel comprises a display element, a sensing element and a control element. The sensing element is arranged to detect an external stimulus and the control element is arranged to generate, entirely within the autonomous pixel, a control signal to drive the display element based, at least in part, on a magnitude of the external stimulus detected by the sensing element. Additionally, the control element comprises one or more groups of transistors, each group comprising two or more transistors arranged to perform the same function and connected in parallel with each other.