Heat engine, an Uncommon card

The card carries these facts from its Wikipedia article.

• While originally conceived in the context of mechanical energy, the concept of the heat engine has been applied to various other kinds of energy, particularly electrical, since at least the late 19th century.
• The heat engine does this by bringing a working substance from a higher state temperature to a lower state temperature.
• A heat source supplies thermal energy that brings the working substance to the higher temperature state.

Rarity in WikiCards follows a year of Wikipedia page views: the most read articles become Epic and Legendary cards. The Heat engine article was read about 62,000 times in a year. ATK comes from the length of the article and DEF from its quality, so this card hits with 69 and blocks with 52: each hit it takes is cut by 21 %.

Open packs. Each pack holds five cards drawn from real Wikipedia articles, the rarest last, and the fifth card is always Rare or better. The odds are shown in the game. A free pack arrives every hour and two can wait, and the Coins you win in duels buy more packs.

The cards just above and just below Heat engine in the power ranking, all domains together.