Structures near the two null-points over the western bipole in AIA 304 Å observations and in the simulation. Panel a: apparent J-shaped brightening in the AIA 304 Å observations on 21 April 2013 at 22:24 UT, east of the western bipole. The J-shape can be extrapolated to form a very weak S shape connecting to the western negative polarity sunspot (white dashed line). Panel b: clearer forward S at the same position 22:36 UT. Panel c: J-shaped structure in the simulation on 21 April at 22:00 UT (white-dashed curve) arising from the field lines connecting the western positive polarity to a low-lying null and the western sunspot (yellow-purple-colored field lines). Panel d: shows how the field lines in panel c are part of a larger positively twisted collection of arcades (yellow-purple-colored field lines). Rainbow-colored lines illustrate the positively-twisted QSL boundary field overlying the main FR (also shown in Fig. 7b at a later time), which connect to a null-point above the western bipole.