There is, and it's basically touch typing. Past a certain point you stop reading each cell. You hold the row number in your head and sweep along the column numb

There is, and it's basically touch typing. Past a certain point you stop reading each cell. You hold the row number in your head and sweep along the column numbers, computing one answer ahead of where your writing. Easy-rows-first is the beginner optimization; pipelining is what the genuinely fast kids are doing!