Extension I: C4 links between PITs formed from On-wall addimers
Horizontal addimer on the wall of (10,0) tube (7/4/7 defect, least favorable)
Chiral addimer on the wall of (10,0) tube (7/5/5/7 defect, more favorable)
Horizontal addimer on the wall of (6,6) tube (7/5/5/7 defect, most favorable)
A C4 link formed from two addimer as in c.