Canvas.setpenopacity(1);
const turtle = new Turtle();

function walk(i) {
    turtle.penup();
    y = -35 + 3 * i
    turtle.goto(-50, y);
    turtle.pendown();
    
    for (j = 0; j < 1000; j++) {
        turtle.goto(turtle.xcor()+0.1,
            y - j * 0.05 +
            Math.sin(j*0.2) * j/1000.);
        turtle.left(1)
    }
    
    return i < 40;
}