How do I make two whiles work together at the same time?

I want to know what can I do to make two whiles work together. for example: Matrix[0][1], Matrix[0][2]... I already tried the program below but it didnt work.

cd = open("Matriz.txt", "a+", encoding="utf8")
count = 0
count2 = 0
count3 = 0
count4 = 0
while (count < 256):
    count = count +1
    print(count)
    cd.write(f'elif R == {count}:\n')
    count2 = count2 + 1
    if count2 < 16:
        count3 = count3 + 1
        cd.write(f"    Matrix[{count2}]")
        if count3 < 16:
            cd.write(f"[{count2}] = 'X'\n")
cd.close()