1. Draw two shapes: A circle and a rectangle
2. Select both shapes, hold down the Alt key, click and drag to create 4 copies.
3. Select the first pair of shapes and open the Pathfinder tool using Window > Pathfinder
4. First is the the Divide tool. This separates the shapes into sections and eliminates overlap.
5. Select the next pair and click the Trim tool. This is like the Divide tool but the overlap doesn't get its own shape; the top shape is left intact.
6. Select the next pair and click the Merge tool. This is like the Trim tool, preserving overlap, but also merges same-color shapes.
7. Select the next pair and click the Crop tool. The crop tool is a cookie cutter; it eliminates everything outside of the top shape.
8. Select the next pair and click the Outline tool. This is like the divide tool, but converts the shapes to outlines.
9. Select the last pair and click the Minus Back tool. It's like the minus front tool, but the opposite.
10. Remember to Ungroup to use the new paths.