anchor.diff:  	//If not already queued and there is work to be done
   	if(NOT_QUEUED_ALREADY && (fa_len != a_len || fr_len != r_len ))
   		QUEUE_FOR_COMPILE
  +	UNSETEMPTY(add_overlays)
   
   /atom/proc/add_overlay(list/overlays)
   	if(!overlays)
  
positive.code: 	if(!overlays)
  		return
  	overlays = build_appearance_list(overlays)
  	LAZYINITLIST(add_overlays) //always initialized after this point
  	LAZYINITLIST(remove_overlays)
  	var/a_len = add_overlays.len
  	var/r_len = remove_overlays.len
  
negative.code: #define QUEUE_FOR_COMPILE flags_1 |= OVERLAY_QUEUED_1; SSoverlays.queue += src;
  /atom/proc/cut_overlays()
  	LAZYINITLIST(remove_overlays)
  	remove_overlays = overlays.Copy()
  	add_overlays = null
  
  	//If not already queued for work and there are overlays to remove
  	if(NOT_QUEUED_ALREADY && remove_overlays.len)
  