ient(runge_xs[i])-5.5, y_to_client(runge_ys[i])-5.5);
    }
    runge_context.strokeStyle="#AA3311";
    runge_context.stroke();
    runge_context.closePath();

    // guides
    if(do_guides){
        min_d = Math.pow(runge_xs[0] - client_to_x(client_x), 2) + Math.pow(runge_ys[0] - client_to_y(client_y), 2);
        min_i = 0;
        for(var i = 1; i < runge_n; ++i){
            var di = Math.pow(runge_xs[i] - client_to_x(client_x), 2) + Math.pow(runge_ys[i] - client_to_y(client_y), 2);
            if(di 