anchor.diff:  
   -include_lib("proper/include/proper.hrl").
   
  --export([g_mapjson/0, g_name/0, g_color/0, g_opacity/0, g_color_rgb/0,
  +% higher level structurs
  +-export([g_mapjson/0, g_combatantjson/0]).
  +% more nuts 'n' bolts
  +-export([g_name/0, g_color/0, g_opacity/0, g_color_rgb/0,
   	g_color_rgba/0, g_256/0, uniquify/1]).
  +
  +%% higher level
   
   g_mapjson() ->
   	?LET(X, list(oneof([
  
positive.code: 			{5, char()}
  		])
  	), unicode:characters_to_binary(N)).
  
  g_color() ->
  	oneof([
  
negative.code: 		{gridline_color,  g_color()},
  		{grid_opacity,  g_opacity()}
  	])), uniquify(X)).
  
  g_combatantjson() ->
  	?LET(X, list(oneof([
  		{name, g_name()},
  		{color, g_color()},
  		{portrait_image, g_url()},
  		{token_image, g_url()},
  		{x, integer()},
  		{y, integer()},
  		{layer_id, choose(1, 3)},
  		{initiative, float()},
  		{size, pos_integer()},
  		{aura_size, non_neg_integer()},
  		{aura_color, oneof([null, g_color()])}
  	])), uniquify(X)).
  
  %% nuts n bolts
  
  g_name() ->
  	?LET(N,
  