To keep things interesting-I recently installed a 3 phase panel in a new home. I then subfed two single phase panels from the 3 phase panel-each single phase panel uses 2 phases from the 3 phase panel.
Technically, these are different and have different potential issues (from harmonics) than a true single phase/split phase panel.
Not that the distinction makes much difference to most people-especially those that will do 120 volt wiring, but are afraid to do "220" wiring because it is more dangerous.