Vector.left

assert(Vector!(T, 2).zero == Vector!(T, 2)(0, 0));
assert(Vector!(T, 2).one == Vector!(T, 2)(1, 1));
assert(Vector!(T, 2).up == Vector!(T, 2)(0, -1));
assert(Vector!(T, 2).right == Vector!(T, 2)(1, 0));
assert(Vector!(T, 2).down == Vector!(T, 2)(0, 1));
assert(Vector!(T, 2).left == Vector!(T, 2)(-1, 0));