I got a note recently from Don Knuth. He had exhumed some old notes, on finite algebraic systems with a binary operator that satisfies the axiom B.AB = A. He called them Gropes. I briefly called them Babagroups, as a reminder of the axiom. The formal name is Semisymmetric Quasigroups. Don's note includes a short six page summary of Grope properties, including some constructions and the relationship with Steiner Triples. It's pretty dense. I haven't fully grokked it, but he doesn't seem to mention our group's discovery about the number of idempotents mod 3. The most interesting part was toward the end: He wrote a program to count the non-isomorphic systems, to contribute to Sloane's database. He found my numbers (thanks, Neil), hence the note. Meet me at 1,1,2,3,4,9,41,595,26620,3908953,1867918845. I'm the guy with purple hair. Rich