1 If we go to a wedding with more than 367 people, there must be people from the same Amanome (not in the same year).

This is the pigeon coop principle.

Put m things into n empty drawers at will (m >；; N), then there must be at least two things in a drawer.

Since there are 366 days in a year at most, at least two of these 367 people were born on the same day in the same month. This is equivalent to putting 367 things into 366 drawers, and at least two things are in the same drawer.

In winter, cats always hold their bodies in a ball shape when they sleep, because this gives off the least heat.

In mathematics, an object with a certain volume and the smallest surface area is a sphere.

Shrinking the cat into a sphere can reduce the contact area with the outside world, reduce the speed of heat exchange, reduce the speed of heat loss, save energy and keep the body temperature.

Why are all wheels round and not other shapes?

The center of the circle is called the center of the circle, and the distance from any point on the circle to the center of the circle is equal. Make the wheel round, and the axle is at the center of the circle. When the wheel rolls on the ground, the distance between the axle and the ground is always equal to the radius of the wheel.

So people sitting in the car can be pulled away smoothly by the car. If the wheel is deformed and not round, and the distance from the wheel to the axle is not equal, the car will not be stable again.