Dyad

The dyad, ditelon, dion or simply line segment, is the only possible 1-polytope (rarely polytelon). Its facets are two points. It appears as the edges of all higher polytopes.

A dyad is simultaneously the 1-simplex, the 1-hypercube, and the 1-orthoplex. Furthermore, a dyad is the pyramid, prism, tegum, ditope, and hosotope of the point. It may also be considered a 0-hypersphere.

Congruent dyads can tile 1D space as the regular apeirogon.

Vertex coordinates
Coordinates for the vertices of a line segment of length 1 are simply the points:
 * $$\left(\pm\frac12\right).$$

Representations
The dyad has two distinct representations:


 * x (full symmetry, vertices are the same)
 * oo&#x (vertices considered of different types)