Bring to boil:

1/2 cup margarine
1/2 cup brown sugar
1/2 cup milk

Take off heat, and add:.

1 tsp. vanilla
1 cup crushed graham wafers
1/2 cup chopped walnuts or pecans
1 cup coconut

Line a 9x13 pan with whole graham wafers, spread above filling over wafers, add another layer of wafers.  Cover with the following icing:
Cook together until thick:

2 Tbsp. flour
1/2 cup milk

Cool then beat together in separate bowl:

1/4 cup butter
1/4 cup shortening
1/2 cup white sugar
dash of vanilla
pinch of salt

Add cooled flour mixture, beat until smooth, then spread.  Refrigerate squares.