Pyramid
hexagonal pyramid
a heptagonal pyramid
A 3-sided pyramid.
A pyramid
a scalene pyramid.
Triangular Pyramid.
A tetrahedron (a triangulat pyramid).
It is a pentahedron. One example of an irregular pentahedron is the 4-sided pyramid.
square rectangular It can be any polygon shape, depending on how many sides the pyramid has. A four sided pyramid would have a quadrilateral (like a square or a rectangle) base, for instance.
A 6 sided planar (2-d) polygon is called a hexagon.A 6 sided 3-d shape is a hexahedron, which might also be a cube, rectangular prism, die, pentagonal pyramid, or quadrilateral di-pyramid depending on the exact shape.
A cube, a rectangular prism and a pentagonal pyramid