The next diagonal would be 2; doesn't matter if the diagonals are sequential or not, each one alternates. If you're on 2 and you have 1 movement point left, you

The next diagonal would be 2; doesn't matter if the diagonals are sequential or not, each one alternates. If you're on 2 and you have 1 movement point left, you can't use it for a diagonal. You could track the state across turns for slightly more accuracy, though we haven't ever bothered to do that when we use this method in D&D. Even perfectly implemented, it's still just an approximation. But the simplest version works pretty well: "Every diagonal move, regardless of direction or sequence, alternates between costing 1 movement point and 2." And most of the time you're attempting to move in a straight line anyway, so you rarely have to deal with double-backs or non-sequential diagonals.