A quarter in which a team scores zero or three points — a failure to execute rather than a defensive stop, and a signal that the under is live.
TODO — write this one yourself. The concept is yours and the page only works if the reasoning is too.
TODO — cover at minimum: why zero and three get grouped together, why a no-show quarter by either side counts rather than only the favorite's, and how many of them it takes before you'd act on it.
Math, not advice. 21+ where legal. If gambling stops being entertainment, call 1-800-GAMBLER.