This is a repository that isolates a bug in the 'arcade' library for Python. The bug happens when the player moves on a moving platform, and ends his movement in between two blocs. Here, the platform blocs alternate between two textures, in order for the bug to be more easily visible. When this situation happens, the player slides until it is completly on one bloc, and this can happen either in the same direction as the original movement, or in the opposite direction. The player sometimes even moves back and forth. The physics engine used in this project is the "arcade.PhysicsEnginePlatformer" engine. There is nothing implemented in this project except the A and D keys to move the player left and right, the ESC key to reset the game, four moving blocs and the player.