Find the coefficients of the plane equation
plane_coefficients(p, n)A point on the plane (or N x 3 matrix of multiple points)
vector normal to the plane (or N x 3 matrix of multiple vectors)
a matrix with 4 columns a,b,c,d where ax + by + cz + d =
  0
Both p and n can accept multiple points/vectors to 
  calculate many planes at once.
Other geometry: 
intersect_plane()