Gladyn and Don inherit a car worth 800. They agree to settle the ownership by means of sealed bids. The high bidder gets the car by paying his brother the amount of the high bid. If the bids are equal - which they may well be, because they agree to bid in hundred-dollar quantities - the ownership is determined by the toss of a coin, there being no exchange of funds. Gladyn has 500 on hand, whereas Don has 800.
How should they bid?
This zero-sum game has more than one saddle-point (both players could bid $3$ or $4$ or play a mixed strategy over those two bids). When a zero-sum game has multiple saddle-points, equilibrium outcomes are equivalent (they give the same payoffs) and interchangeable (you can swap them). Therefore, from a strategic viewpoint, there are multiple optimal bids (3 or 4,or a mixed strategy).