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.
When something reforms into a new shape, this process is called "restructuring" or "reforming." It involves changing the structure or form of an object to create a different shape or configuration.
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 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.
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.
It is said to be 'similar'
That shape is called an 'oval' or an 'ellipse'.
It can be called anything, depending on what it actually is.But it's described as 'congruent' to the first one.