Single Beam Reflection
The expanded laser beam, diverging, is coming in from above left. You can see with only an approximate 50 degree reference angle, the plate needs to be considerably larger then the object such that the top of the plate does not bisect the object (object shadow is very near top of plate shadow) or one could choose a shallower object. With the addition of black tape across the top of the plate (not shown here) to elliminate internal reflections, the top edge of the plate shadow whould be thicker and darker.
The expanded laser beam, diverging, is coming in from above and just to right of camera view.