text: Sankar Chatterjee determined in 2005 that , in order for Microraptor to glide or fly , the fore and hind wings must have been on different levels ( as on a biplane ) and not overlaid ( as on a dragonfly ) , and that the latter posture would have been anatomically impossible .
simplified: Sankar Chatterjee found that , in order for Microraptor to glide or fly , the fore and hind wings must have been on different levels ( as on a biplane ) and not overlaid ( as on a dragonfly ) .