Preheat oven to 350° F

In saucepan, combine sugar, cocoa, and flour

Add margarine and milk

Cook until mixture begins to boil, stirring constantly

Remove from heat

Add a small amount of hot mixture to eggs and combine

Return mixture to pan

Fold half can of pie filling into mixture

Pour into pie crust

Bake at 350° F for 35 to 45 minutes, or until center is set, but still shiny

Cool

Chill for 1 hour

Combine 2 cups whipped topping and grated chocolate

Spread over cooled pie

Combine remaining pie filling with remaining whipped topping

Top pie with cherry whipped topping mixture

Chill 1/2 hour