Nepal is an outlier when it comes to flag shape, as it stands out from the norm (rather “two triangles stacked on top of each other”) since according to them: the flag represents Himalaya Mountains & both religions: Hinduism & Buddhism, also the red triangular flag has been a Hindu symbol of victory since the writing of Ramayana and Mahabharata.
That is in contrast to most countries flags as a majority are rectangular in their shape (no matter where from USA, UK, Canada, Japan, Germany, Poland, etc.). I mean, why are most flags rectangle by default rather than being unique on using another shape? I mean, Nepal is the only country where a flag is designed from another shape that differs from a rectangle.
Not just mass-manufacturing - because of how they work, the rectangle is the default shape of cloth produced on any loom.
A shape like a right-angled triangle is pretty easy to produce from a square or rectangle, so if it was only that reason we would also see a lot of right-angled triangle shaped flags.
Could it be that the physics of the shape makes rectangles more resiliant as flags (as in, remaining at least partially intact) in the wind?
Or maybe it’s some Historical reason that boils down to some common origin of that shape as tradition?
Or maybe a bit of all including ease of manufacturing?
Somebody call Sheldon, we gots questions about flags.