How to assemble four children's curved ruler pistols

The ruler used by Chinese police is true, but the revolver used by foreigners is definitely an old calendar book. The advantages of revolver are simple use (loading and pulling the trigger), very high reliability (no problems of automatic loading and magazine spring fatigue, no dependence on recoil), simple cleaning and maintenance, ability to shoot again in the case of blind fire, and high accuracy (fixed position of barrel and sight).