I am working on a plugin that will allow players to join worlds, play on them, then leave. When the player leaves the world, I need the world to be rolled back 100% (blocks, chest contents, sign data, entities, etc.) I must be 100% automated, This could be done one of two ways: 1. Log all changes to a world then undo them when the player leaves. 2. Replace the world with a backup when the player leaves. If anyone can help, I will give them a staff position on my server (this plugin will run the server).