+ x, y = symbols('x y')
+ self.square1 = Polyhedron(inequalities=[x, 2 - x, y, 2 - y])
+ self.square2 = Polyhedron(inequalities=[x - 1, 3 - x , y - 1, 3 - y]) #correct representation
+ self.square3 = Polyhedron(inequalities=[x, 3 - x, y, 3 - y])
+ self.square4 = Polyhedron(inequalities=[x - 1, 2 - x, y - 1, 2 - y])
+ self.square5 = Polyhedron(inequalities=[x - 3, 6 - x, y - 3, 6 -y])
+ self.square6 = Polyhedron(equalities=[3 - y], inequalities=[x - 1, 3 - x, y - 1])
+ self.unbound_poly = Polyhedron(inequalities=[x, 3 - x, y])
+ self.universe = Polyhedron([])
+ self.empty = Empty
+ self.disjoint = And(Ge(x, 0), Ge(-x + 2, 0), Ge(y, 0), Ge(-y + 2, 0))
+ self.complement = Or(Ge(-x - 1, 0), Ge(x - 3, 0), And(Ge(x, 0), Ge(-x + 2, 0), Ge(-y - 1, 0)), And(Ge(x, 0), Ge(-x + 2, 0), Ge(y - 3, 0)))
+ self.hull = And(Ge(x, 0), Ge(-x + 2, 0), Ge(y, 0), Ge(-y + 2, 0))
+ self.dropped = And(Ge(y, 0), Ge(-y + 2, 0))
+ self.sample = And(Eq(y - 3, 0), Eq(x - 1, 0))
+ self.intersection = And(Ge(x - 1, 0), Ge(-x + 2, 0), Ge(y - 1, 0), Ge(-y + 2, 0))
+ self.union = Or(And(Ge(x, 0), Ge(-x + 2, 0), Ge(y, 0), Ge(-y + 2, 0)), And(Ge(x - 1, 0), Ge(-x + 3, 0), Ge(y - 1, 0), Ge(-y + 3, 0)))
+ self.sum1 = Or(And(Ge(x, 0), Ge(-x + 2, 0), Ge(y, 0), Ge(-y + 2, 0)), And(Ge(x - 1, 0), Ge(-x + 3, 0), Ge(y - 1, 0), Ge(-y + 3, 0)))
+ self.sum2 =And(Ge(x, 0), Ge(y, 0), Ge(-y + 3, 0), Ge(-x + 3, 0), Ge(x - y + 2, 0), Ge(-x + y + 2, 0))
+ self.difference1 = Or(And(Eq(x - 3, 0), Ge(y - 1, 0), Ge(-y + 3, 0)), And(Eq(y - 3, 0), Ge(x - 1, 0), Ge(-x + 2, 0)))
+ self.difference2 = And(Ge(x + y - 4, 0), Ge(-x + 3, 0), Ge(-y + 3, 0))
+ self.lexmin = And(Eq(y, 0), Eq(x, 0))
+ self.lexmax = And(Eq(y - 2, 0), Eq(x - 2, 0))