code: def triangle_coordinates(i, j, k):
      
  
      return [(i, j, k), (i + 1, j, k - 1), (i, j + 1, k - 1)]
docs: Computes coordinates of the constituent triangles of a triangulation for the
      simplex. These triangules are parallel to the lower axis on the lower side.
  
      Parameters
      ----------
      i,j,k: enumeration of the desired triangle
  
      Returns
      -------
      A numpy array of coordinates of the hexagon (unprojected)