Does "FOIL" (first outer inner last) or the distributive property make more sense for your understanding of the expansion of (x+h) * (x+h) in algebraic terms? One thing I love about math is how there are different ways of representing the same concepts -- geometric, algebraic, etc. I wonder if this is because different mathematicians in history had different thinking styles, and paved the way for us modern folk to learn math in the format that works for our own unique minds.