Square base and four sides that come to a point. Simple enough, yet rich in symbolic meaning.
The image (above, right) is in Mexico. Although it does not come to a full point, it is considered a pyramid. A pyramid must have a square (all sides being equal) at its base, with lines drawn from four corners upward to meet at what is (or would be) a point (the apex). This is the essential structural definition. I have often heard people refer to tetrahedrons as pyramids. In fact, the popular “pyramid” shaped tea bag is in fact a tetrahedron.
Platonic Solids
The five platonic solids
The tetrahedron is the first in a series of five shapes referred to as the platonic solids (after Plato). They are (in order) Tetrahedron, Cube (Hexahedron), Octahedron, Dodecahedron, and Icosahedron. The tetrahedron is a form made of four connected equilateral triangles. The five platonic solids are distinct in that all of their sides are the same shape.
Defining a Pyramid
A good pyramid definition is that, in contrast to the tetrahedron, the pyramid combines a single square and four triangular sides, equal in shape. The pyramid shape can be elongated or flattened and remains a pyramid as long as it remains three-dimensional. The only difference among pyramids, outside of the material they are made of, is the angles of its sides, dictating how steep the pyramid is. Certain slopes, such as the Giza, are often treated as a canonical form.
In modern usage, pyramids are most often encountered as meditation tools rather than monumental architecture. For those new to the subject, reviewing basic questions can help clarify common misunderstandings, while understanding basics around form and proportion supports informed choices. This kind of starting knowledge helps ground later experiential work.
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