p1 = p_X(1, 1, p_X(1, 0, NULL));
p2 = p_X(1, 1, p_X(-1, 0, NULL));
p3 = p_X(1, 5, p_X(-2, 4, p_X(1, 0, NULL))); 
print_X(add_X(p1, p3));
print_X(add_X(p1, p2));
print_X(mul_X(p1, p2));
print_X(mul_X(p2, p3));
print_X(pow_X(p2, 5));
print_X(eval_X(pow_X(p1, 16), p_X(1, 0, NULL)));
print_X(eval_X(p1, p3));
print_X(eval_X(p3, p1));