ynthesis_xs[1]), y_to_client(synthesis_ys[1]));
    synthesis_context.moveTo(x_to_client(synthesis_xs[synthesis_n-2]), y_to_client(synthesis_ys[synthesis_n-2]));
    synthesis_context.lineTo(x_to_client(synthesis_xs[synthesis_n-1]), y_to_client(synthesis_ys[synthesis_n-1]));
    synthesis_context.strokeStyle="#AA3311";
    synthesis_context.stroke();
    synthesis_context.setLineDash([]);
    synthesis_context.closePath();

    // guides
    if(do_guides){
        min_d = Math.pow(synthesis_xs[0] - client_t