Social games publisher Zynga gets a lot of bad press for the similarity of some of its games to titles by other developers and publishers. Yet it’s also true that a lot of companies are cribbing from Zynga’s mobile hits.

Here are two new examples: Word Chums and Sudoku Together, which both owe something of a debt to Zynga’s series of With Friends games.

Word Chums is the work of developer PeopleFun, and is getting some traction on the App Store. Like Words With Friends, it wraps social gaming around Scrabble, with virtual coins, challenges and achievements.

Meanwhile, Sudoku Together (pictured) applies the With Friends format to Japanese number-puzzles – something Zynga has yet to do – with more coins, asynchronous multiplayer and Facebook connectivity.