I am looking for solution to style the symbol in mapserver; with polygon outlined with simple line along with filled triangle inward like below

[![enter image description here][1]][1]

; I tried creating symbol with following way

    SYMBOL
      NAME "Inward line"
      TYPE vector
      POINTS
       0   0
        5  10
        10  0
            
        
      END # POINTS
      ANCHORPOINT 0.5 0
    END # SYMBOL

with line symbols adding together,. but no luck,. 


  [1]: https://i.sstatic.net/MB13w.png