Crowdsale English Auction

In an English auction crowdsale model, buyers place bids, competing with each other to set the highest price.

Every higher bid displaces an earlier bid. If no competing bidder challenges the current bid within a given time frame, the bidder who placed it becomes the winner.

In a variation of this, the seller sets a minimum price for an item. If no buyer places a higher bid than this minimum price, the item remains unsold.