Canvas.setpenopacity(1);

// Global code will be evaluated once.
const j_step = 3.5 // min = 0.5, max = 5, step = .1
const x_delta_shift = 7.9 // min = 0.1 max = 10 step = .1;
const y_delta_shift = 5.9 // min = 0.1 max = 10 step = .1;
const sin_mag = 2.7 // min = 0 max = 10 step = 0.1;
const sin_frequency = 0.2 // min = 0.1 max = 5 step = 0.1;
const max_line_length = 3 // min = 1 max = 10 step = 1;
const boarder = 10 // min = -10 max = 10 step = 1;
const angle_range = 19 // min = 0 max = 180 step = 1;
const turtle = new Turtle();
x_circle = 0;
y_circle = 0;

// The walk function will be called until it returns false.
function walk(i) {
    i = i - 100 + boarder;
    for(let j = -100 + boarder; j < 100 - boarder; j += j_step) {
        length = j/x_delta_shift - i/y_delta_shift;
        if(length > 0) {
            while(length > max_line_length) {
                length -= max_line_length;
            }
        }
        else {
            while(length < -max_line_length) {
                length += max_line_length;
            }
        }
        angle_line = Math.random()*angle_range;
        current_x = j;
        current_y = i + sin_mag*Math.sin(j * sin_frequency);
        
        turtle.penup();
        turtle.goto(current_x + Math.cos(angle_line * Math.PI / 180)*length/2, current_y + Math.sin(angle_line * Math.PI / 180)*length/2);
        turtle.pendown();
        turtle.goto(current_x - Math.cos(angle_line * Math.PI / 180)*length/2, current_y - Math.sin(angle_line * Math.PI / 180)*length/2);
    }
    
    return i < 100 - boarder;
}