Lungta or windhorse. This is printed at the centre of many Buddhist prayer flags surrounded by mantra  or dhāraṇī usually with a dragon garuda, tiger, and snow lion printed in the four corners..
The wind horse represents the bodhisattva Prince Sidhartha's faithful horse Kanthaka. and symbolises the union of the four elements of personal vitality.

This drawing is based on an element from old Bhutanese xylograpgh for printing prayer flages
Own work
Christopher J. Fynn