Likely for reasons due to balance. If the fan were asymmetrical, it would be out of balance. Putting the same 'stuff' on both sides balances it out. Joe M. Jesse Lackey wrote: > And as other people have mentioned, there are 2 pulses on the signal > line per revolution, not 1, curiously! -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist