It's called a mobius strip.
A cone has one vertex and one edge.
A circle. A Moebus strip.
They are the corners of any quadrilaterals but in a shape of a rough surface that has a pointy edge that can also be a fourth angle.
A cone.
half a sphere
A line?
sphere
The shape with just one surface is.... a sphere.
A cone has one vertex and one edge.
In geometry, the only shape that has one surface is a plane.
triangle
A cone has one vertex, one edge, and one base.
a sphere
There is no solid that has those characteristics. To have an edge it must have another surface.
its a lens...1 curved edge = a circle, 1 flat surface = back, 1 curved surface = front. (these are used in some battery-less flashlights, as an example.)
A circle?
A cone.