Stones on the plane

For discussing Olympiad Level Combinatorics problems
adam23
Posts:13
Joined:Mon Oct 29, 2012 8:00 pm
Stones on the plane

Unread post by adam23 » Sun Nov 18, 2012 2:25 pm

We’ve got 4 stones and we put them on the plane in points (0,0), (0,1), (1,0) and (1,1). In one move we choose one stone and we change his position symmetrically under one of another stones. Is it possible that after finite discontinuity numbers of moves, three stones belong to one straight?

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