Spread 1/2 cup pecans in thin layer on an ungreased cookie sheet. Combine butter, sugar, corn syrup and water in heavy saucepan. Let come to boil and cook 5 minutes. Add whole almonds. Stir constantly. Cook until thickened (285° or 290°) . Pour over pecans immediately. Place plain chocolate candy bars on top. When melted, spread chocoloate over toffee. Sprinkle 1/2 cup pecans over melted chocolate. Cool. Mark off or cut candy into squares.