//ey, try to edit the code var x = 300; var y = 100; var vel = 0; var dt = .2; var K = 0.5; // <= change this to 0.2 loop = function() { ctx.clearRect(0, 0, 600, 600); ctx.fillRect(x, y, 20, 20); y += vel*dt; vel += 9.8*dt; if(y >= 580) vel = -vel*K; }