I wasn't sure, but I thought that there was an even older game that was extremely similar to 2048 and Threes. I remember people got upset when the Threes developers accused 2048 of cloning them [0], because they thought Threes was itself a clone of something earlier.

[0] http://asherv.com/threes/threemails/#letter

Please don't be rude in Hacker News comments.

2048 is most definitely a clone.