That year-long journey of adding mechanics and art for testing, only to strip them away and get back to the core game again and again wasn't wasted; the amount of testing and failed experiments gave them a sense of purpose and clarity when it came to the final game. It needed to be small, simple and easy to understand. The visual information needed to be clear and readable. Every other concept or theme was thrown out in deference to the original idea of matching tiles in multiples of three.
Threes is a fun and addictive game.