Teacher-created performance assessments can lead to deeper learning and powerful changes in instructional climate. Three students, one teacher, and a computer engineer sat around a table. Each student gave a five-minute presentation of a mathematical argument, using models and images in a digital platform to support his or her position. Students’ topics ranged from triangle congruence to what type of 3—D solid makes the most efficient ship-ping container to get aid to a disaster zone. Afterward, the individuals at the table discussed the information, analyzed the argument, and progressed together toward deeper understanding of the mathematical relationships discussed.