In message <[log in to unmask]>, [log in to unmask] writes >worker cells >drawn one at a time in free space would also be round. I read somewhere they are round if done by one bee. Crowded bees make their cells the right distance apart (in relation to their body size) centre to centre, so they have to make hexagonal cells in making the shared walls - draw a series of circles that overlap perfectly and you'll get hexagons. Actually, I regularly offer comb to children to ask them what they see and then ask simple questions to get them to enlarge on their answers. When a boy said he saw a 5-sided cell, I did not contradict - as mothers usually do (and this one did) I asked to be shown it - sure enough he had found one of the very few transitional cells that actually had 5 sides - a quite good looking pentagon. -- James Kilty