Two pentagons

Two Pentagons is a group dynamics Brain game for two groups of 6 to 20 players.

Required material
Two ropes of about five metres length (longer for bigger groups)

Procedure
The players are divided into two groups of the same size. Both groups are given (independently from each other) the following task:
 * As a group, you have to form the shape of an n-gon with this rope (the number of corners derives froom the number of people in the group PLUS one; in the case of a group with 6 people, this

would result in a heptagon).
 * The n-gon has to be equally shaped and with the corners pointing to the outside (mathematically spoken: onefold, non-crossing, planar, konvex, equally measured).
 * Every member is only allowed to touch the rope with their right hand.
 * Further aids are not allowed (such as trees or posts in order to make up for a missing corner).
 * As soon as the task has been fulfilled, all members of the group raise their left hands.

Solution
The players will puzzle over the solution for some time and present a variety of solutions. Communication is the main goal. The journey is the destination.

The correct/favoured solution is: the two groups work together. The n-gons are positioned in such a way so that they touch at one edge.The two corners of this edge are formed by the one

member of each group who holds the ropes of both groups in their right hands. By doing this, the missing corner point is formed by a member of the other group.