(assert (= x0 1))
(assert (= x1 0))
(assert (= x2 3))
(assert (= x3 -2))
(assert (= x4 1))
(assert (= x5 -4))
(assert (= x6 -4))
(assert (= x7 0))
(assert (= x8 1))
(assert (= x9 3))