If it is your surface then whatever you like. And if it is not yours, then nothing - without the owner's permission.
A flat surface is no more that a plain horizontal surface with no depth. For example the surface of a table top is a flat surface, that is the surface only, not the depth of the top or the rest of the table
Plate Tectonics, to put it simply.
You place your bottom on a flat, level surface; and put your weight on it. It's that simple.
It does not have a flat surface.
The surface area of a cone is: Curved Surface: pi X the radius X L (L is the slant of the cone pointing to the tip. \ ) Flat Area/Base: pi X the radius *squared* easy.
The flat surface that goes on and on in all directions has no boundaries. This flat surface is called infinite surface. Accordingly, the answer is that the flat surface that goes on and on in all directions is called an infinite surface.
A flat, level surface is a plane.
A plane is a flat surface with no thickness
Put your one hand on the base and the other on the arm, and put your microscope on a flat surface.
A mirror with a flat surface - planar
It is a drawing of the earth on a flat surface
Its base is a flat surface