Admittedly, handling minus in the corner piece is complicated, and may not be worth doing is time is at a premium. Still, it provides a fun late-in-the-year review, and is of interest to many students. On the other hand, note that other algebra manipulatives cannot handle minus in the area model in a geometrically correct way. Using the techniques shown in this video, polynomial long division can be modeled with Lab Gear. This is addressed only in Algebra Lab: High School, Chapter 6, pp. 77-80.