Block   
  superclass: Tactical-Mission-Task 
  superclass: Block 
  agent: Military-Unit <----> Actor  
  base: Military-Unit <----> Acted on 
  object: Place <----> Location            [This is defined as the Block Line in Morrison's document] 
  instrument: Tangible-Entity plays Barrier 
  objective: Make-Inaccessible with 
                       agent:  M-U called "friendly forces" 
                       object: Place 
                       base: MU called "enemy forces" 
                  Action with 
                       prevents: Move 
                                         object: MU called "enemy forces" 
                                         direction: *forward 
                                         path: Avenue-of-Approach 
                        
                      
 
Note:  The military block concept is close to the core library block. 
Note: agent is required (see 3 below) 
Note: Direction *forward presupposes notion of Advance 
 
Block (E). 
=====. 
1. Block is a tactical mission task that denies the enemy access to an area or prevents his advance in a direction or along an avenue of approach. 
2. A blocking force may employ blocking obstacles to assist in the task. 
3. Obstacles alone cannot accomplish a blocking task. 
4. Block as a tactical mission task differs from the tactical mission task of fix because a blocked enemy force can move in any direction other than the obstructed one, while a fixed enemy force cannot move in any direction. 
