simplices

/ˈsɪmplɪsiːz/
noun
  1. Plural of simplex: the simplest geometric shapes in a space, such as a triangle in two dimensions or a tetrahedron in three dimensions.
    • The mathematician drew several simplices on the board to illustrate her theory.
    • In topology, simplices are used to build complex structures called simplicial complexes.
    • The students constructed simplices out of straws and connectors for their project.