Concept #1 - Stacks And Screens

Concept #1 - Stacking and Screening: 

While this concept is technically illegal, it is widely used by many teams. Players take set positions in a certain formation ( varies), and in sequence certain players move to "screen" ( block) some opposition players, allowing 1 or 2 players time to get separation from their opponent to receive a pass.

Screens can be used for kick outs , set plays, and even during open play.