Understanding Boundaries

The purpose of the exercise is to demonstrate boundaries and should only take 2-3 minutes:
Take an even number of people and divide them into two lines, line A and line B. The two lines should face each other at a distance of about 10-15 feet apart. Each person in line A is paired to someone in line B, with whom they'll be asked to have a normal conversation. Every 10-15 seconds, ask the people in line A to take a step toward their partner in line B while still carrying on their conversation. Repeat this until the participants are practically standing nose-to-nose. Break up the activity, and when everyone is sitting down, ask them how they felt.