The 63 points needed for the bonus in the upper half
corresponds to getting three of each die type in each row. If
you score more than three dice in the fives and sixes rows then
you can afford to place a bad roll in either the ones row or the
twos row and still get the bonus.
Don't forget about multiple yahtzees, if you roll a second
yahtzee you can also put it in the yahtzee row for even more points.
