# Rotate them to make the problems more interesting:
  arot1 = pi/7; arot2 = pi/9
  tab = rn.rotate2(tab[0:2],arot1) + rn.rotate2(tab[2:],arot2)
  va = rn.rotate2(va[0:2],arot1) + rn.rotate2(va[2:],arot2)
  vb = rn.rotate2(vb[0:2],arot1) + rn.rotate2(vb[2:],arot2)

  ua1,um,un,ub1 = sploine_arc.bezier_controls(sta,stb, Lab)
  assert ua1 == ua
  assert ub1 == ub