Crust: 
1 1/2 cups finely crushed chocolate wafers
 6 tablespoons butter, melted

Filling:
 3 8-ounce package cream cheese, softened
 1 1/2 cups sugar
 2 tablespoons all purpose flour
 1/8 teaspoon salt
 4 eggs
 4 squares (4 ounces) semisweet chocolate, melted
 1/4 cup milk
 1 teaspoon vanilla

Topping:
 1 square (1 ounce) semisweet chocolate
 1 teaspoon butter

 For crust, in a bowl combine chocolate wafer crumbs and melted  butter.  Press crumb mixture firmly on bottom and 1 3/4 inches up  sides of a 9-inch springform pan.

 For filling, in a large mixer bowl beat cream cheese till creamy.  Combine sugar, flour and salt; stir into the cream cheese mixture.  Add eggs all at once.  Beat just till combined.  DO NOT OVERBEAT.  Stir in the 4 squares melted chocolate, milk and vanilla till  combined.  Turn into crumb-lined pan.

 Bake in a 325 oven for 60 minutes or till center appears set.  Remove from oven; cool 15 minutes.  Loosen sides of pan.  Cover  and chill at least 2 hours.

 In a small saucepan over low heat melt the 1 square semisweet  chocolate and butter.  Drizzle in lattice design atop cheesecake.  Chill till chocolate is set.