MATLAB: How to generate location of matrix

Question

1.how to generate location (1,1) of matrix 2. For example, we may have a 512×512 pixel image, on which we impose a grid of 512×512 threads that are subdivided into thread blocks with 8×8 threads each, for a total of 64×64 thread blocks. how to generate location (1,1) of matrix on each block 8×8 for 64x64thread blocks?i would like to get location (1,1) on each block 8×8 then multiply with 0-255.

thanks

Answer 1

B2(1:64:end, 1:64:end) = 255;