#define FIRE  8//1000
#define WOOD  4//0100
#define ELEC  2//0010
#define WATER 1//0001

proc/strength_of(element) 
     return ((element<=1)? (element >> 1) : (8))

proc/weakness_of(element)
     return ((element>=8)? (element << 1) : (1))

//This is defined for atom/movable, but it could be changed based on what you need it for.
atom/movable

    //The Overlays list, that will have our overlays in readable datums.
    var/list/Overlays
    
    proc
    
        //This proc only accepts only /image arguments 
        overlayAdd()
            
            //Checks if the list is initialized, and if not, the list gets initialized
            if(!Overlays)Overlays=new
            
            //Loops through all the /image objects in the arguments
            for(var/image/I in args)
                //Adds each one to the Overlays list
                Overlays.Add(I)
                
            //Call the update proc
            overlayUpdate()

        //All the arguments can either be text strings 
        //that correspond to the tag on a /image object in the Overlays list
        //or /image objects that are equivalent to objects already existing in the list.
        overlayRem()
        
            //Loops through the arguments
            for(var/o in args)
                //Checks to make sure there's something in the Overlays list
                if(Overlays && Overlays.len)
                    //Variable I that is of type /image
                    var/image/I
                    //The following if checks if the argument is a tag,
                    //and if so, it will use locate() to retrieve an image with that tag.
                    if(istext(o))
                        I=locate(o)
                    
                    //The following else if checks if the argument is an image
                    //and if so it set's I equal to the argument
                    else if(istype(o,/image))
                        I=o
                    
                    //Removes I from the Overlays list and checks if the Overlays list should
                    //be cleaned up.
                    Overlays.Remove(I)
                    if(!Overlays.len)Overlays=null
                    
                else
                    //Breaks if there is nothing in the Overlays list to remove
                    break
                    
            //Call the update proc
            overlayUpdate()

        //This proc should be called whenever the Overlays list is updated,
        //or if anything inside the Overlays list is updated.
        overlayUpdate()
        
            //Nulls overlays list
            overlays=null
            
            //Searches for all the /image objects in the Overlays list,
            //and adds it to the overlays list.
            for(var/image/I in Overlays)
                overlays.Add(I)

//This proc is pretty self-explanatory, it returns a /image given certain arguments
proc/Image(icon/icon,icon_state,atom/loc,pixel_x=0,pixel_y=0,layer=FLY_LAYER,tag)
    var/image/I=new
    I.icon=icon
    I.icon_state=icon_state
    I.loc=loc
    I.pixel_x=pixel_x
    I.pixel_y=pixel_y
    I.layer=layer
    I.tag=tag
    return I

overlayAdd(Image('sword.dmi'))
//with icon_state
overlayAdd(Image('sword.dmi',"wield"))