Why is the table in the interrogation room triangular?

This kind of table was designed by the British and has been in use ever since. When triangles sit together, they don't have to face each other, so they can observe better.

The triangle is usually in the room where the suspect asks and confesses, because in every room where the confession is recorded, there will be one or more cameras to shoot during the suspect's questioning and confession. You can clearly photograph the situation under the tripod, whether the suspect recorded a statement under duress, and if necessary, the recording may be used as evidence in court.