塗りつぶされたらせんを描く.

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Sub Test_Fill()
    Const A = 1, B = 0.2
    Dim Theta() As Double, Xf() As Double, Yf() As Double
    Dim X() As Double, Y() As Double, X2() As Double, Y2() As Double
    Dim D As Double, N As Long, I As Long, J As Long
    Dim Fig As Figure, Ax As Axs
    N = 8 * Pi() / 0.1 + 1
    ReDim Theta(N - 1), Xf(2 * N - 1), Yf(2 * N - 1)
    ReDim X(N - 1), Y(N - 1), X2(N - 1), Y2(N - 1)
    Set Fig = Plt.Figure()
    Set Ax = Fig.Gca()
    For I = 0 To N - 1
        Theta(I) = I * 0.1
    Next
    D = 0
    While D < 2 * Pi()
        For I = 0 To N - 1
            X(I) = A * Cos(Theta(I) + D) * Exp(B * Theta(I))
            Y(I) = A * Sin(Theta(I) + D) * Exp(B * Theta(I))
            X2(I) = A * Cos(Theta(I) + D + Pi() / 4) * Exp(B * Theta(I))
            Y2(I) = A * Sin(Theta(I) + D + Pi() / 4) * Exp(B * Theta(I))
        Next
        For I = 0 To N - 1
            J = N - I - 1
            Xf(I) = X(I)
            Yf(I) = Y(I)
            Xf(N + I) = X2(J)
            Yf(N + I) = Y2(J)
        Next
        Call Ax.Fill(2 * N, Xf(), Yf())
        D = D + Pi() / 2
    Wend
    Call Plt.Show
End Sub