It's not just a game, ...

... it's an an application of polynomial least squares to build a fundamental economic model.

The price modifier was a particularly important addition, because it worked to reduce purchasing power over time. Essentially it meant that for particularly wealthy players, merchants would always sell for more and buy for less, a clever move that prevented a player from abusing the system and attaining infinite wealth. The final version of Steinke's system, which took everything he learned and wrapped it up in some software, was called "Reactor." Instead of setting a static value, Reactor calculated prices at run-time, making every trade unique and creating a living economy where every item had a different value based on the type of merchant the player was interacting with and the state of the world around them.