sounds like the triple town/yeti town fiasco a couple of years ago.
The developers (Spry Fox) of triple town had the original idea, the yeti town "developers" (LOLAPPS Inc. and 6Waves LLC) just copied them.
Anyways... threes currently has about 10K - 50K installs on google play, 2048 clones all together have approximately 2000K - 10000K installs.
The only real difference between the two? Threes costs $1.99, 2048 is free.
it is interesting to see that the free app's total user base is approximately 200x the size of the paid-for apps user base. Imagine if they had released it for free and put ads on there.
for comparison: flappy bird had about 50000K installs...
There may be a good chance the threes developers would win if they took the other guys to court, but 2048 can be released by any guy who has the ability to checkout a git repository on github and package it into an android app.