Mix oats, brown sugar, margarine and syrup thoroughly.
Divide the mixture between two 2-quart glass utility dishes.
Press evenly into dishes and bake each separately for 3 minutes, 30 seconds on high, uncovered, until entire top is bubbly.
In a bowl, melt chocolate pieces and peanut butter for 1 minute, 30 seconds, on high, uncover, stirring midway through cooking time.
Stir until smooth and spread on top of oatmeal mixture.
Keep in refrigerator.
The squares will seem too hard to cut, but after a few minutes at room temperature, they will soften.
Cut each dish into 24 squares.