Swans arch their heads to preen themselves
Whilst in architecture arches can be ornate
plain or bricked in
usually straddling allowing passage underneath although sometimes on top as well.
Domes too take many shapes from onion
but all sit on top.
The only thing that I found that had all three aspects of this challenge was in a shopfront window down on the river. Would you claim these? They are perhaps slight more than half a circle, their dome fitting snugly into someones roof of mouth whilst the arch is formed if we could only see it from the rear.
In response to Cee’s Fun Foto Challenge