Heat oven to 450. Have a baking sheet ready. In a medium bowl, mix flour, baking powder, baking soda and salt. Cut in margarine with pastry blended, or work in with fingertips until lumps are no larger than small peas. Stir in buttermilk with a fork until mixture clumps together. Press dough into a ball. On a lightly floured surface with a lightly floured rolling pin, roll dough into a 10x6-inch rectangle. With the long edge facing you, fold in both short ends so they meet in center. Fold dough in half (as if you were closing a book), forming a packet 4 layers thick. Roll dough into a 15 cm square. With a floured knife, cut dough into 16 squares, using a straight downward motion with each cut (don't saw dough). Place biscuits 4 cm apart on ungreased baking sheet. Bake 10-12 minutes until biscuits are lightly browned. Removed to a wire rack to cool. Recipe By : Woman's Day 10-8-96