As participants enter a session, have them choose a single post-it from a selection of 4-5 colors. The first time they talk should be with a shoulder-buddy, to relieve the tension of not knowing those nearby. Then later, the participants stand to the aisles and find a group of 3 (avoid threesome or three-way . . . triad is a safe term) where each person is a DIFFERENT color of post-it.
There is a small anxiety of "what if I'm the odd-man-out . . . I hope a group wants my color" that turns into relief when they find their group. The relief and excitement is desirable--the bond made with the group this way is stronger than if they simply had to find the others in the room with the same color or number.
Always have more than 3 colors.
Watch for the ones who are still holding their post-its up when groups have formed. Simply gesture to them to join a nearby group, making it four, while announcing "Some of you will be groups of 4."
Related strategies: Color Card Grouping
Submitted by: Tim Chase