When a fly lands on the ceiling, does it do a half roll or a half
"I once saw a slo-mo film of a fly doing this. As far as I can
recall, the fly first does a "zoom" towards the wall, so that its
body is inclined upwards maybe 45 degrees instead of being level.
Next, it reaches forward and up with its front legs ahead of the
flapping wings. Together with the body angle, the fly can point its
front legs almost straight up. As soon as one or both of them snag
the ceiling, it stops flapping and pulls its behind under itself so
it can latch on with the rear legs."
-- Mark Drela)