LOCKJAW Tetromino Game was a PC-based training tool for the video games Tetris DS and Tetris Party Deluxe. It is no longer available here for two reasons.
First, online multiplayer in Nintendo DS and Wii games using Nintendo Wi-Fi Connection was powered by the GameSpy service, which shut down on May 31, 2014. This makes online multiplayer in these games impossible and thus makes LOCKJAW unnecessary.
More importantly, the lead developer of LOCKJAW is a fan of free software, or software that the public can improve and share, as a means to protect the rights of users of computing devices. He does not share the belief expressed by Alexey Pajitnov, co-founder of The Tetris Company, that free software "should never have existed" because it "destroys the market." (Mr. Pajitnov explained further in a 2015 interview with Matt Barton.) But what really destroys the market is monopoly.
In fact, though Mr. Pajitnov and his partner Henk Rogers want Tetris to become an internationally competitive sport, as Mr. Pajitnov mentioned in earlier in the same interview, a policy against free software makes it that much harder. Imagine if there were a Basketball Company LLC that could sue a city or school district for copyright infringement for putting a basketball court with correct dimensions into a city park or school gymnasium. There are multiple competing suppliers of basketball and chess equipment, unlike software for playing Tetris. This is why Chess is a sport and Tetris is not: Chess has no owner.