I number each row.Then I number each block, say that each row has 5 blocks I will the in each left corner pin (1-1),(1-2,(1-3),(1-4),(1-5) and the second row I will , will start with( 2-1),(2-2),(2-3), do you see where I am going with this you do that with every row, I just use the little pastie notes. goed luck sarah