If we had ruined the last iteration what would we have done?
You start the activity by asking: 'If we had completely ruined last iteration what would we have done?' Record the answers on a flip chart. Next question: 'What would be the opposite of that?' Record it on another flip chart. Now ask participants to comment the items on the 'Opposite'-chart by posting sticky notes answering 'What keeps us from doing this?'. Hand out different colored sticky notes to comment on the comments, asking 'Why is it like this?'.