anchor.diff:  
   % API
   -export([start_link/1]).
  --export([add_entity/2, remove_entity/2, get_entity/2, update_entity_state/4]).
  +-export([add_entity/2, receive_entity/2 remove_entity/2, get_entity/2, update_entity_state/4]).
   -export([client_request/6, client_event/5]).
   
   % Internal
  
positive.code: 	gen_server:start_link(?MODULE, Args, []).
  
  %% --------------------------------------------------------------------------------------------------------------------
  %% Enitty API
  %% --------------------------------------------------------------------------------------------------------------------
  
  %% --------------------------------------------------------------------------------------------------------------------
  
negative.code: 
  handle_call({update, EntityID, _OldEntState, _NewEntState}, _From, State) ->
  	Entities = State#state.entities,
  	%TODO: Compare OldEntState to the current entity's state. If the match, we then update to NewEntState. Otherwise,
  	% we error.
  	NewState = State#state {
  		entities = lists:store(EntityID, #entity{}, Entities)
  	},
  