Strassen's algorithm recursive matrix multiplication

Question

I am trying to use Strassens algorithm to multiply two matrices recursively. I want to keep dividing the matrices into 4 parts until I end up with a matrix of 1x1 == base case of 1. I've worked it out by hand, and I've checked every 2x2 and 1x1 calculation on several calculators and my answers are right, but when I try to combine the 2x2 in the last part (the final r, s, t,u 2x2 matrices that will equal the new matrix) I dont seem to get the right answer. About 90% of my final matrix is wrong, but the individual 2x2 and 1x1 are correct. This should be the answer, but instead I get something else.