Distinct from xa'a, though regrettably proposed at around the same time. Proposed by Gerald Koenig:

• http://balance.wiw.org/~jkominek/lojban/9411/msg00186.html (actual cmavo settled on in http://balance.wiw.org/~jkominek/lojban/9411/msg00254.html)
• Also on thread starting with http://balance.wiw.org/~jkominek/lojban/9412/msg00296.html