edge
A 3D semi circle
it if called a edge for a 3D shape
A cone perhaps?
A cone.
edge
An edge.
A 3D semi circle
An impossible shape!
CONE
Cylinder
it if called a edge for a 3D shape
A cone perhaps?
A cone.
you call it a edge
2D shape = Decagon 3D shape = Decahedron
nonahedron