Effect of cell movement on accuracy. Spatial delay in response due to time spent in changing the direction of the switch. The population is growing from the centre of the longitudinal trap (cells washed out at edges) and the image is taken after 300 hours. The middle sector of the trap (light gray) has only one input (case 1/0) at a high level (4.5nM, which leads to a NOR function), and the remaining area (dark gray) has no input (logic case 0/0). The velocity vector field (lower image) shows the direction and magnitude (colour scheme) of the speeds of every cell at the same time (300 hours).