-- Arrow
-- color is (255,255,0);

scale is (1, 1);
-- size is 10;

origin is (450, 450);
rot is pi;
for t from 0 to 400 step 1 draw( t, t );


-- 心形曲线

origin is (200, 200);
rot is pi/2;
-- size is 5;

-- 圆润型
-- color is blue;
scale is (50, 50);
for t from -pi to pi step pi/200 draw((2*cos(t) - cos(2*t)),  (2*sin(t)-sin(2*t))  );

-- 尖锐型
origin is (200+80, 200+80);
-- color is red;
rot is pi;
scale is (8, 8);
for t from 0 to 2*pi  step pi/200 draw( 
            16*(sin(t)**3),  
			13*cos(t) - 5*cos(2*t) - 2*cos(3*t)-cos(4*t)
	  );