For over a decade, Which One Doesn't Belong? (WODB; Danielson, 2016) has been a beloved classroom routine that invites students to engage in mathematical decision-making and justification. In the WODB routine, four related figures are shown to students, and they are asked to decide which of them doesn't belong with the other three. The beauty of the routine is the variety of ways to be "right." It's what teachers of mathematics would call a "low floor, high ceiling" task. The authors realized that the students who got the most out of the routine were those who tried to figure out an argument for why each of the four figures "didn't belong." This led the authors to think about a revised routine--one where instead of looking for ways a figure did "not" belong, students might look for ways it "did."