To mitigate negative numbers you need to add the length of the array: `i = ((i - 1) + 4) mod 4`
leaving you with: `i = (i + 3) mod 4`
To mitigate negative numbers you need to add the length of the array: `i = ((i - 1) + 4) mod 4`
leaving you with: `i = (i + 3) mod 4`