MathDB
flags by a robot concyclic, equal angle (2021 Novosibirsk Oral Geo Oly 9.2)

Source:

May 25, 2021
Concyclicgeometry

Problem Statement

The robot crawls the meter in a straight line, puts a flag on and turns by an angle a<180oa <180^o clockwise. After that, everything is repeated. Prove that all flags are on the same circle.