clean()
Cleans out unseen triangles
pivot_down()
Pivots a wide data set (one triangle per row) into a long data set (one point per row)
return_rhombus()
Get a starting rhombus
return_starting_circle()
Get a starting circle of rhombi
subdivide()
Subdivides one triangle
substitution()
Apply substitution rules to a data set of rhombi/triangles