SUB show_label(site(,),np(),L,proper$)
    DECLARE DEF proper
    FOR y = 1 to L
        LET yplot = y - 0.5
        FOR x = 1 to L
            LET xplot = x - 0.5
            LET label = site(x,y)
            IF label > 0 then
               IF proper$ = "yes" then LET label = proper(np(),label)
               BOX CLEAR xplot-0.5,xplot+0.5,yplot-0.5,yplot+0.5
               BOX LINES xplot-0.5,xplot+0.5,yplot-0.5,yplot+0.5
               PLOT TEXT, at xplot-0.25,yplot-0.25: using$("##",label)
            END IF
        NEXT x
    NEXT y
END SUB