assert_equal(csp(r4, r1), false);
assert_equal(csp(r4, r2), false);
assert_equal(csp(r4, r3), false);
assert_equal(csp(r4, r4), false);
assert_equal(csp(r4, r1), false);
assert_equal(csp(r4, r2), false);
assert_equal(csp(r4, r3), false);
assert_equal(csp(r4, r4), false);