Every time you drag your Twitter feed downward and let it snap back up to refresh the data, thank Loren Brichter. The man who invented "pull-to-refresh" hit it big with his Tweetie app, and now he's got a hot new mobile game called Letterpress. It's the slickest competitive word game since Words With Friends, but some players are complaining that it's too easy to win if you game the system.

Letterpress players take turn coloring letters on a five-by-five grid, using them to create words. You can re-color letters that opponents have used by using them yourself, and you can protect tiles you've already captured by surrounding them with letters of your color. The game ends when all the letters in the grid have been colored, and the player with more letters in their color is declared the winner.

__Solved Games__There is a perfect strategy for each of these games that will always result in a win or a draw.

Connect Four was solved by James D. Allen in October of 1988. The first player can always force a win.

Tic-Tac-Toe, sometimes called Naughts and Crosses, is so easily solved that it's unknown who was the first to solve the game. Still, there are over a quarter of a million possible ways for games to play out.

Checkers was solved in 2007 by Jonathan Schaeffer and his team. It is the most complicated game yet to be solved.

It's a more mobile-friendly Words with Friends, with an aesthetic clearly influenced by SpellTower and elements of territory-control that add strategic complexity to each match. The game is beautiful, original and plenty fun to play, but some worry that it may already be a "solved game."

Noted game designer Raph Koster, creative director of the Star Wars Galaxies MMO and author of the book A Theory of Fun for Game Design, wrote on Twitter that his early enthusiasm for the game was rapidly fading since he'd found "too many winning strategies."

According to Koster, following a four-step process will ensure victory almost every time:

Play for territory, rather than trying to simply get big words. Expand outward from a single point. Lock down vowels and extenders (such as "er," "ed" and "ly") early. Go for the kill by taking out the last remaining gray tiles once you're already winning.

Other players have reported similar success by following certain strategies, with some saying that they've "solved" the game. But even if these strategies work nearly every time, does that make Letterpress a "solved" game?

It does not, says German chess expert Frederic Friedel, founder of ChessBase.com.

The definition of a "solved game" is rather complex, but it boils down to this: There exist "perfect" moves that will always let a player force a win or a draw, and it is possible to ascertain these moves using either wits or, for more complex games, a computer simulation. Tic-Tac-Toe is a solved game; unless a player makes a dumb mistake, every game will end in a draw.

The board game Connect Four has been solved: The first player will always win if they make the perfect moves, regardless of what the other player does. In the game Chopsticks, the second player can always win.

Only games with no element of chance can be solved; there is always an optimal move in Scrabble and a computer can easily calculate it, but the act of drawing random tiles from a bag means that a player cannot be guaranteed to win every game even if he always plays the optimal move.

The game of chess, says Friedel, could theoretically be solved in this way, but no one has yet done it and he believes that no one ever will.

The reason for this is that the number of potential ways for a chess game to unfold is unfathomably enormous: 10 to the power of 120. This is a figure far greater than the number of atoms in the observable universe.

"If you have a grandmaster playing against a computer, he'll have problems with it," he says.

Chess can be incredibly complex, even when there are only a few pieces left on the board. Friedel says that games where one player has a queen and a pawn versus another with only one pawn are "barely understandable" even to some of the world's top players.

Letterpress is not as complex as chess, but is randomized. This, Brichter says, makes the strategy deeper than Koster suggests.

"There are easy boards with E's and S's which are quick bouts, and tough boards where sometimes the most valuable play is making sure an X stays claimed in a corner," says Brichter. "Sometimes you need to tempt your opponent to play a word, because you know there are an odd number of variations on it that will leave you with the most letters in the end."

Jonathan Schaeffer, dean of the science department at the University of Alberta, says that he enjoyed playing Letterpress, but thinks it is a solvable game. "It would be easy to build a computer program to play it well," he says. "Probably perfectly."

Schaeffer is the author of Chinook, the first computer program to win a human world championship in checkers. He is credited as being one of the members of the team that officially solved checkers in 2007.

But just because a game can be solved by a computer doesn't mean it's a bad game, he says. There's another factor that's more important.

"Humans play only games that are fun," said Schaeffer. "What makes a game fun? Intellectual challenge, social aspects, simplicity of the rules, aesthetics... many things."

Connect Four image: DQMountaingirl/Flickr; Tic-Tac-Toe image: public domain; Checkers image: Steve Snodgrass/Flickr