Bristle Plotting Puzzle.

Simulation results of bristle pattern formation using different models. a) The pattern of gene expression used for the stripe models. Green stripes have almost equal expression of Dl and N genes but ac is not expressed. Blue stripes have high expression of ac and Dl genes but low expression of N gene. Red stripes have high expression of ac and N genes but low expression of Dl gene. Bristles only form in the blue stripes. b) Lateral inhibition with stripes does not ensure equal spacing or good alignment. c) Inhibition field with out stripes ensures proper spacing but does not produce a good alignment. d) Inhibition field with stripes produces equal spacing as well as good alignment.