Editing Biplane (section)

==Avian evolution==
The [[feathered dinosaur]] ''[[Microraptor gui]]'' glided, and perhaps even flew, on four wings, which may have been configured in a staggered sesquiplane arrangement. This was made possible by the presence of flight feathers on both forelimbs and hindlimbs, with the feathers on the forelimbs opening to a greater span. It has been suggested that the hind limbs could not have opened out sideways but in flight would have hung below and slightly behind the fore limbs.<ref name=Chatterjee>Chatterjee, 2007, pp.1576–80</ref>