one.

The entrance is placed in the water of a large freshwater lake, and the outlet is placed on the edge of the desert to receive a wave of strong rainfall. Let me contribute to the greening of the desert.

two.

Sold on the black market, it is claimed that this is a one-time killing machine. The specific method of use is to first cover a person's whole body, such as wearing stockings on the head that are thick enough, and wear casual clothes, but not revealing physical features.

, set the entrance in a place where ordinary people will not find it, and set the exit behind the person who is to be executed. As soon as the killer opens the door, he points the gun at the person and then closes the door and disposes of the crime tools.

Third, if you are a person with a strong sense of justice and will not use this door for personal gain, then leave it to the Foundation. At the same time, you can also get a memory and eliminate the gift package. Of course, the Foundation will definitely treat this

Door.

An experiment is carried out, but after the experiment is carried out once, the item loses its characteristics, and the door that loses its characteristics is just an ordinary door.

Fourth, build a perpetual motion machine.

As the name suggests, it is to create a perpetual motion machine based on the characteristics of any door that can teleport objects instantly.

The entrance is set in the sea deep enough, the exit is set in the air, and the sea water is poured from high altitude into the sea.

The only thing missing is a generator in the middle. As for the question of whether the exit can be set up in the air, there is an episode.

When Nobita and Doraemon went to the beach, they directly set the exit a few meters above the sea level.

But in fact, the power generation efficiency of this kind is really not high. After all, it is limited by the size of the door, the amount of water output per unit time is limited, and there are not many generators that can be installed.

But if you can’t stand it, it’s a perpetual motion machine, so just leave it there and keep generating electricity.