Well, what do you consider "upper-level" math? The original article definitely means graduate level classes, not just advanced undergrad. FWIW, I'm a physicis

Well, what do you consider "upper-level" math? The original article definitely means graduate level classes, not just advanced undergrad. FWIW, I'm a physicist and used not rows or spirals but the "columns" approach mentioned by one commenter. :) And I probably couldn't tell you what type of math I prefer.