How do you fill a surface with rectangles through optimization?

I'm a beginner optimization user and I haven't used it much.

I would like to know if you would know how to perform my optimization problem, I have a 1000X1000 square mesh matrix (each point is one meter away from the next ) with altitude values of the points. I have to create 9 rectangles(1x5) that are as close together as possible and the general shape is as close to a rectangle. (one rectangle can touch others)

To do this, I had thought of giving coefficients to the sides as shown in the picture.

Since the problem is to optimize where to place the rectangles with the least possible slope on each side, a coefficient is calculated with the slope C2=1/(m)

Therefore, the sum of all the coefficients should be maximized, being in the blue

Csum=1* c2(i,j)+1* c2(i,j)+1* c2(i,j)+0* c2(i,j)

Then what should be optimized would be the maximum of the coefficients of the 9 rectangles

Would you know how to perform this problem or another methodology to do it?