(assert (= x0 -2))
(assert (= x1 -1))
(assert (= x2 -4))
(assert (= x3 -4))
(assert (= x4 0))
(assert (= x5 0))
(assert (= x6 1))
(assert (= x7 0))
(assert (= x8 0))
(assert (= x9 -2))