Using a laser source, in a slightly dark space, you can clearly observe the propagation path of light in the air;
– Homemade Corner Reflector
Try to make a corner reflector with the two flat mirrors provided;
– Homemade Periscope
Find a toothpaste box (or similar carton), open a small opening near the ends of the box, each with a flat mirror, two plane mirrors parallel to each other, and at an angle of 45° to the horizontal plane, to make the easiest periscope.