function F = face(kx,ky)
    C1 = circf(kx, ky, 20, 0, 0);
    C_I1 = circf(kx, ky, 3.5, 4.25, 4.25);
    C_I2 = circf(kx, ky, 3.5, -4.25, 4.25);
    C_s1 = circf(kx, ky, 1, 3.4, 3.4);
    C_s2 = circf(kx, ky, 1, -3.4, 3.4);
    
    R_n = rectf(kx, ky, 1.5, 4, 0, -0.5);
    R_m = rectf(kx, ky, 10, 1.5, 0, -5.75);
    
    F = 0.8*C1-0.4*(C_I1+C_I2+R_n+R_m)-0.4*(C_s1+C_s2);
end