Tessera is now a free app on iPhone and Android. Every letter is already on the board, just in the wrong place: swap two tiles until every row spells a word, in as few moves as you can. Since the web launch in May it has grown Tessera Chain, a ladder of levels with stars and timed bonus rounds; daily leaderboards and private leagues; 20 themes, each free to try; Hard mode on 5x5; and Spanish. One puzzle a day, the same for everyone.
