anchor.diff:  	init_order = INIT_ORDER_VIS
   
   	var/list/vis_overlay_cache
  -	var/list/unique_vis_overlays
   	var/list/currentrun
  -	var/datum/callback/rotate_cb
   
   /datum/controller/subsystem/vis_overlays/Initialize()
   	vis_overlay_cache = list()
  -	unique_vis_overlays = list()
  -	rotate_cb = CALLBACK(src, .proc/rotate_vis_overlay)
   	return ..()
   
   /datum/controller/subsystem/vis_overlays/fire(resumed = FALSE)
  
positive.code: 		if(MC_TICK_CHECK)
  			return
  
  //the "thing" var can be anything with vis_contents which includes images
  /datum/controller/subsystem/vis_overlays/proc/add_vis_overlay(atom/movable/thing, icon, iconstate, layer, plane, dir, alpha = 255, add_appearance_flags = NONE, unique = FALSE)
  	var/obj/effect/overlay/vis/overlay
  	if(!unique)
  
negative.code: 
  	if(!thing.managed_vis_overlays)
  		thing.managed_vis_overlays = list(overlay)
  	else
  		thing.managed_vis_overlays += overlay
  	return overlay
  