anchor.diff:  
   
   %random integer generator between Min and Max values
  +
  +-spec randInt (integer(), integer()) -> eqc_gen:gen(integer()).
   randInt (Min, Max) ->
   	eqc_gen:choose(Min,Max).
   
   %maybe its not very efficient
  +
  +-spec randFlt(float(), float()) -> eqc_gen:gen(float()).
   randFlt (Min, _) ->
       ?LET(Flt, eqc_gen:real(), Min + Flt).
   
  +%% candidate for removal
   propname() ->
       name().
   
  +
  +% candidate for removal
   name() ->
       eqc_gen:non_empty(eqc_gen:list(eqc_gen:choose($a,$z))).
   
  
positive.code: 
  -compile(export_all).
  
  %-define(debug,true).
  
  -ifdef(debug).
  -define(LOG(X,Y),
  
negative.code: 
  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  %% Integer generators
  
  -spec integer () -> eqc_gen:gen(integer()).
  integer() ->
      eqc_gen:int().
  
  -spec multiple_of (integer()) -> eqc_gen:gen(integer()).
  multiple_of(M) ->
      ?LET(N, integer(), M * N).
  
  -spec multiple_of_min(integer(), integer()) -> eqc_gen:gen(integer()).
  multiple_of_min(Mul,Min) ->
      MinMul = Mul * (1 + (Min-1) div Mul),
      ?LET(N, nat(), MinMul + Mul * N).
  
  -spec multiple_of_max(integer(), integer()) -> eqc_gen:gen(integer()).
  multiple_of_max(Mul,Max) ->
      MaxMul = Mul * (Max div Mul),
      ?LET(N, nat(), MaxMul - Mul * N).
  
  -spec multiple_of_min_max(integer(), integer(), integer()) -> eqc_gen:gen(integer()).
  multiple_of_min_max(Mul,Min,Max) ->
      MinMul = (1 + (Min-1) div Mul),
      MaxMul = (Max div Mul),
  