Sometimes new mechanics are required to solve well-known gameplay problems. This is a typical scenario in live games (for example mobile games or Massively Multiplayer Online Games), where the game is constantly updated and adjusted to meet its audience's evolving needs. But it might as well be the case for sequels, franchises, and final releases after an alpha or a beta test.
One great example is the Chest mechanic in Clash Royale, one of the most interesting game mechanics in the history of mobile games (and one that has contributed to the incredible success of Supercell's real-time PvP title.)
This is how it works:
In Clash Royale, by winning a battle, players win chests. Chests contain Cards and Gold, ...
