(2*x - y)*(2*x + y) + (2*x + y)*(-1)
-y - 2*x + (y + 2*x)*(-y + 2*x)
-1.0*y - 2.0*x + (y + 2.0*x)*(-y + 2.0*x)
2 2 -y - y - 2*x + 4*x
(y + 2*x)*(-1 - y + 2*x)