a) NST TiO (7057 Å) image overlaid by HMI magnetogram contours of positive (white) and negative (black) polarities. The contour levels are ±200 and ±500 gauss. b)–d) NST Hα+0.8 Å and Hα line center images showing two loop systems (L1 and L2) and their connectivity (marked by plus and minus signs). The size of each image a)–d) is ~50′′× 35″. Each division on the x- and y-axes is equal to 1″.