The 2x2 matrix is about as simple as a chart can be: Just take two factors that have some relationship with one another, assign one the horizontal axis and the other the vertical axis.

I am using a fragment shader to, among other things, calculate the eigenvectors of a 2x2 matrix.I can calculate the eigenvalues just fine using the quadratic formula on the characteristic equation ...

I have found that one of the best frameworks for helping get things done is the classic “urgent vs. important” two-by-two matrix.