The word you are looking for may be "transformation".
They're not always. But anytime something is not a pyramid shape, it's not called a pyramid,it's called something else. So everything that's left ... all the things that are a pyramid shape ...is called a pyramid.
I reckon, if a 70 sided shape is called a heptacontagon, and a 50 sided shape is called a pentacontagon, then a 40 sided shape might be called a quadracontagon, or something along those lines.
symmetrical shapes
When something changes like that it is called transformation.
A liquid.
A nine sided two dimensional shape would be called a nonagon. Nona is a common prefix meaning nine of something.
That shape is called a cylinder.That shape is called a cylinder.That shape is called a cylinder.That shape is called a cylinder.
In theory, the most sides a shape can have in three dimensions is 10,100. It is called a Googolgon. It actually stands for something that is unattainable.
Because if they were not circular they would be called something else, wouldn't they? Possibly elliptic, or "a flattened squarish shape" or "a wiggly shape".
A line which divides a shape in two is called a bisector.
That shape is called an 'oval' or an 'ellipse'.
It is said to be 'similar'