Step 1: To Do a Periscope You Need!
In today's instructables I'm going to show you the idea of how to make a periscope.
Step 2: Periscope Is One of the Simplest Optical Appliances, Which Can Be Made at Home.
Step 3: It Is Convenient for Watching Through the Crowd at Races and Competitions.
You may observe sea nature without coming up to surface.