When we first debuted this series early in the season, I mentioned that our decision to group Cal games into three types of clusters could expand to four or more clusters as we continue accumulating data. In fact, I noted that if we simplified recent Cal games into a 2x2 box we’d have plenty of data in three of the categories—good defense + bad offense, good defense + good offense, and bad defense + bad offense—but not much data in the good offense + bad defense box. Our clusters don’t exactly map onto those breakdowns, but it’s a reasonable approximation. Following a spate of worse-than-usual defense coupled with more-productive-than-usual offense (though turning that productivity into points remains a challenge), the algorithm has now given us a bona fide fourth cluster of games: The Pillowfights!