Magnification map around a 1 M_⊙ embedded in a macrolens potential with magnification µ_t = 100 and µ_r = 2. The gray scale shows the magnification with the critical curve around the microlens forming a standing hourglass figure. The blue, almost horizontal, thin curve marks the region where the residual R_y ~ 0. The wide green curve marks the corresponding region where the residual R_x ~ 0. Arcs form in regions where both blue and green curves overlap, that is, when the condition in Eq. (3) is satisfied. The yellow rectangle encloses a small region shown in the cartoon representation of Fig. 2. The gray scale shows the logarithm of the magnification. The direction of the tangential and radial components of the magnification are marked in the horizontal and vertical direction respectively.