-sq5 = Le(1, x) & Le(x, 2) & Le(1, y)
-sq6 = Le(1, x) & Le(x, 2) & Le(1, y) & Eq(y, 3)
-u = Polyhedron([])
-x = sq1 - sq2
+sq5 = Le(1, x) & Le(x, 2) & Le(1, y)
+sq6 = Le(1, x) & Le(x, 2) & Le(1, y) & Le(y, 3)
+sq7 = Le(0, x) & Le(x, 2) & Le(0, y) & Eq(z, 2) & Le(a, 3)
+p = Le(2*x+1, y) & Le(-2*x-1, y) & Le(y, 1)
+
+
+universe = Polyhedron([])
+q = sq1 - sq2
+e = Empty