I can chart this out for you later, but I have to start the laundry or we will be snowed under! If you want to get started, just count how many half sq triangles there are , how many red blocks, how many black blocks how many white background blocks. It looks like she did just random red/black hst. you could plan them out if you like, but I like this scrappy look.
(I didn't notice the tan in there too!)