It starts with k cliques of size 1, which are sorted in increasing order by the amount of missing data they contain.
second, it reflects a concrete technique by which regular sound Greek z u g o n th u g a (ter-) -n u -(os) e r u th (rós) Regular sound correspondences across four Indo-European languages, illustrated with help of alignments along the lines of Anttila (1972, page 246).