Which pyramids don't have parallel faces?

Pyramids that do not have parallel faces are known as irregular or non-regular pyramids. Unlike regular pyramids, where the base is a regular polygon and the triangular faces are congruent, irregular pyramids can have bases of varying shapes and sizes, leading to non-parallel faces. An example of this is a pyramid with a base that is a scalene triangle, where the triangular faces can differ in size and shape.