The number of the member stars vs. the ages of the sample clusters. The sizes of the open circles in the panel are proportional to the overall ellipticities of the sample clusters. The red open triangle in the panel indicates the cluster NGC 6791. The two black dashed lines are the boundary lines of different partitions. The two partitions in the left half of the panel are marked as Region B and Region A, from top to bottom, with Region C and Region D in the right half. A legend to display the scales of those open circles is on the right side of the figure. Given that the definition of supercluster masses (massive (> 10⁵ M_⊙; Emig et al. 2020)) and assuming that the average mass of every single star is about 1 M_⊙, the right end point of the x-axis in the panel is set to 5.