Step 4: Analysing the Pattern
Tip: To scale a pixelated image without artifacts, select "Interpolation: none"
Being lazy and obsessive is a bad combination. I wrote a python script to count up how many tiles of each kind I would need. Because I was too lazy to learn how to use a module that can read most image formats, I converted the image to ascii pbm format in order to read and manipulate it conveniently.
My chosen maze is 41x55 pixels; I need 65 each of the 3/1 units, and 410 2/2 units, plus some extra dark pairs for the edge.