The Odd Shape Out task was an open-ended problem that engaged students in comparing shapes based on their properties. Four teachers submitted the work of 116 students from across the country. This article compares various student's responses to the task. The problem allowed for differentiation, as shown by the many different ways that students could decide which shape was the odd shape out. In addition, students from all middle school grade levels could access the problem. It also addressed several of the middle-grades content standards and several of the mathematical practices. Students used Common Core's Standards for Mathematical Practice (SMP), in particular, SMP 6 (using precise vocabulary) and SMP 7 (seeing structure among the shapes). As they compared their answers and debated the validity of other points of view, they were also engaging in SMP 3 (making arguments and critiquing the reasoning of others) (CCSSI 2010). [This Solve It task first appeared in the December 2015/January 2016 issue.]