In this possession based drills, teams will play 4v4 in 2 seperate grids. Each player is numbered 1 to 4 within each grid. Whilst play is ongoing, the coach will shout out a random number between 1 and 4.   

The number in which the coach shouts must quickly switch to the other grid, making play unbalanced for several seconds.   

The quicker the players react to the switches, the more chance their team have of maintaining or winning possession.