Unlocked is a game I came up with about 5 years ago (Early 2010). There I was sitting in a stuffy meeting with a board of engineers working through an issue we were having on a government contract. The problem is that we had to embed a cryptographic engine into a small portable device. We had to figure out how to handle different types of keys and they each worked a little bit different. The problem wasn’t just in identifying the differences but then enforcing that each key were handled by its own methods.
Immediately my mind started racing with building unique keys. The idea of set collection had been around for sometime. As in ticket to ride, collecting sets of the same colors would yield you the victory, in my game different patterns of colors would yield progress. An example would be that instead of 5 oranges to build a route, you could build a route using yellow, orange, red, blue, red. Thematically this would be important because the key you would build would not be digital (as in my inspiration) but rather a mechanical key.