text: Countermobility
  Table 17-1. Tactical obstacle effects
  Function Template Example
  Note. Symbols colored gray are used to help
  explain how the control measure is used and
  are not a part of the control measure.
  Obstacle effect symbols
  Obstacle effect describes the effect that the commander wants obstacles and
  fires to have on the enemy (see ATP 3-90.8/MCTP 3-34B)
  Block
  An obstacle effect that
  integrates fire planning
  and obstacle effort to
  stop an attacker along a
  specific avenue of
  approach or to prevent
  the attacking force from
  passing through an
  engagement area.
  Disrupt
  An obstacle effect that
  focuses fire planning
  and obstacle effort to
  cause the enemy to
  break up its formation
  and tempo, interrupt its
  timetable, commit
  breaching assets
  prematurely, and attack
  in a piecemeal effort.
  Fix
  An obstacle effect that
  focuses fire planning
  and obstacle effort to
  slow an attacker’s
  movement within a
  specified area, normally
  an engagement area.
  Turn
  An obstacle effect that
  integrates fire planning
  and obstacle effort to
  divert an enemy
  formation from one
  avenue of approach to
  an adjacent avenue of
  approach or into an
  engagement area.
  17-23. Obstacle effects and their symbols resemble some of the tactical mission tasks and symbols
  described in Appendix A. However, obstacle effects and obstacle effect symbols differ from tactical mission
  tasks and tactical mission task symbols. Tactical mission task symbols are used during COA development to
  show information (the what or why) about a friendly force action. Obstacle effect symbols are used during
  COA development to show how obstacles will support each COA. Obstacle effects must support tactical
  mission tasks, but the best way to do that may require designating an obstacle effect that differs from the
  supported tactical mission task or placing it in a different location; for example, achieving the tactical mission
  task fix in a specified location may require turn or block obstacle effects in front of, behind, or adjacent to