[jim_0068]

Sure

- Put one the infamous dowels across your shoulders and hold with your hands
- Make a backswing shoulder turn
- Now make a downswing where the dowel "traces" the plane line

If the dowel is outside the plane line you are "roundhousing" and if the dowel is inside the plane line you are "using perverted axis tilt" and are underplane.

Let me also add that both contribute to bending your plane line as well.