Structures of NGC 3242. The left panel shows the [N II] λ6584 map from MUSE datacubes where the LISs and the nebular inner and outer shells are indicated. The middle panel illustrates the ratio 8.0/4.5 of IRAC bands, where three rings and the halo are visible. The final figure is an RGB image (R: [N II] λ6584, G: Hα, B: [O III] λ5007) from HST data, which shows the rim and the blobs.