A question from Erdős
In the picture there are 12 points forming a convex polygon with threefold rotational symmetry.
The points are inside the union of the red parallelograms and the angle is acute.
These conditions guarantee the existence of points so that the resulting 15-gon satisfies the following:
For every point in the boundary of there is a circle centred at that intersects the boundary of at least 6 times.