(assert (= x0 2))
(assert (= x1 -2))
(assert (= x2 -4))
(assert (= x3 -3))
(assert (= x4 0))
(assert (= x5 0))
(assert (= x6 2))
(assert (= x7 2))
(assert (= x8 -4))
(assert (= x9 -3))