Photoelectric control of fireworks display and circuit knowledge of light cube application;

Large armored vehicles have wide wheels or tracks, which can reduce the pressure on the ground by increasing the contact area with the ground. The principles of leverage and balance are used in the construction of floats and stages.

When the motorcade is moving, the vehicles are moving relative to the ground, but any two vehicles are relatively stationary. When the troops marched, they heard slogans, and their voices were generated and spread.