Of all the lines in ORF that have back to back pairings (2+3, 2+2,...etc) I have yet to find even one sequence that is commutable one either side. The last 4 months in ORF my lines have been commutable on at least one side... this is getting stupid. Of the 48 lines in ORF next month only 12 of them don't have back to back pairings.