Antique Illustration (copper engraving) of a Wind-Blade, or a Seventeenth Century Ventilation System or Fan., 1662

an illustration of a boy and a girl in a hot air balloon

Smoke ring. This is a poloidal (rotating) vortex flow that is stable for considerable distances in still air. The rotating flow is maintained by the viscous friction between the moving ring and the stationary air outside it.

A woman flying on the back of a dove towards the sun

A man flying towards a light at the end of the tunnel

A man swinging on a tree swing over a river

Flora & Fauna - line art - a 19th century engraving Animal - mammal - the class Aves Bird Swallow A small bird, noted for its speed and its ability to stay in the air for long periods to capture insects. Certain species are migratory.

A woman with drinks flying over a couple on a beach

Diagram of the condition of strabismus, where one eye cannot focus with the other; view of eyeballs and their musculature from above with lines of vision indicated; note that right eye has an elongated muscle which does not allow it to turn the eyeball fa

A whale with a sailboat inside of it

A bird with a berry in its beak

A bird piercing a pumpkin with its beak

Air conditioning unit in Singapore