const s = 0xff;
const density = 0.45; // min=0.1, max=2, step=0.001

const turtle = new Turtle();
turtle.penup();
turtle.goto(-s, 0);
turtle.pendown();

function walk(i) {
    turtle.forward(s);
    turtle.left(density);
    turtle.backward(s);
    return i < 0x168 / density;
}