Question 58
Let $n \ge 3$ be a given positive integer, and suppose $n$ points are marked on a circle. Anna and Elsa play the following game: starting with Anna, they take turns choosing three of the points that have not been used yet and drawing the triangle with these vertices; the triangle may not cross any side of a triangle that has already been drawn. The first player who cannot draw a triangle satisfying these conditions loses, and the other player wins. Who has a winning strategy? (The answer may depend on $n$.)