from pygeo import * v=display(scale=5, camera_vector=(0,1,-1)) zpoint=zFreePoint(1,3,color=BLUE) zOrthoPoint(zpoint,color=RED) #reference objects usphere=uSphere() upoint1=z_to_uPoint(zpoint,color=WHITE) u=u_to_zPoint(upoint1,color=WHITE) upoint2=uAntiPodal(upoint1,color=WHITE) rLine(upoint1,upoint2,seg=True,color=WHITE) rLine(usphere.N,upoint1,color=WHITE) rLine(usphere.N,upoint2,color=WHITE) zPlane(color=MAGENTA) v.pickloop()