Strata 21

Strata 21 is a single-player puzzle game from eBrainyGames. It has been included in more than one of eGames compilations, Office Games and Galaxy of Games: Green Edition.

The player is dealt a pack of cards in a pyramid arrangement. This leaves just four cards available to start with, the lower level cards only coming into play when they are exposed. The object of the game is to make up twenty hands of cards containing as many combinations of twenty-one as possible. Each hand must be completed within a time limit and successive hands score progressively more bonus points

In the first round, the Jack's Round, the player must make hands with a minimum spot value of seventeen, in the second round - the Queen's round - that value has increased to eighteen, and so on.
The game records just the highest score that has been achieved and the object is to beat that score on successive plays. When it was released it was possible for players to compete with other players by uploading their scores to an on-line Hall of Fame. In 2015 the site which supported this feature is no longer active