Ilya's logical tests
This problem was offered at the Moscow City Mathematical Olympiad for high school seniors in 1978, the finals.
A policeman is patrolling the streets assigned to him according to the map below, and initially stands at the central intersection. Somewhere on these streets there is also a thief. The policeman cannot see the thief unless located on the street on which the thief walks. It is known that the thief's speed is less than half of the policeman's speed. You are the policeman. Catch the thief.
To move, click in the green area and then use the arrow keys. You may also use PageUp, PageDown, Home and End keys to move all the way to the next intersection in the desired direction. NOTE: IF YOU ARE NOT GETTING KEYBOARD RESPONSE, PLEASE USE MOUSE LEFT CLICK OUTSIDE THE BOARD AREA AND THEN INSIDE THE BOARD.