User blog comment:Hyp cos/SCG(n) and some related/@comment-31495349-20200108224722/@comment-31495349-20200109183145

Weiermann and Buchholz might indeed match up here. So maybe I'm too optimistic, and K3_3 corresponds just to ϑ(Ω3), while Petersen graph to ϑ(Ω4).