_client_y_center - i*chebyshev_client_y_step + 16);
    }
    chebyshev_context.strokeStyle="#000000";
    chebyshev_context.stroke();
    chebyshev_context.closePath();

    // polynomial
    var A = [];
    var B = [];
    for(var i = 0; i < chebyshev_n; ++i){
        A[i] = [];
        for(var j = 0; j < chebyshev_n; ++j){
            A[i][j] = Math.pow(chebyshev_xs[i], j);
        }
        B[i] = chebyshev_ys[i];
    }

    X = solved_linear(A, B, chebyshev_n);

    chebyshev_context.beginPath();
    f