You might say, the Fan in the foreground is the predecessor of the two fans propelling the 'flying insect'. They are not to dissimilar in concept and both rely on aerodynamic forces to turn or provide propulsion. From a technological view point this is a thought provoking shot. Nicely framed by a wonderful halo.
Thanks guys for the comments.....but confession time...
this windmill stands only 1.5 metres and the fan diameter is 36cm!!
It was made by my Dad and actually pumps water.