Mathematics as a means to stop snoring

A flag waving in the wind can illustrate what we call "air-solids interaction". When the wind hits the top of the flagpole the flag dances to the wind's rhythms, often in complex ways.  And as we all know: it takes two to tango. The air-flow is also influenced by the flag's movements; the direction and speed of air-flow changes along the flag's surface. This constitutes what is known as a two-way fluid-structure interaction (FSI).