A laminated card. The card lists out various things that individuals use to guide their decisions and interactions on a day to day basis. These cards are found throughout the office: on desks and in meeting rooms. I often find myself, and see others, picking up the card during discussions to remind myself of values and concepts that should be guiding decisions.
In the lower section of the card it lists the key points of the mutual learning model and eight behaviours for smarter teams (from Roger Schwarz & Associates). These points show up in various ways, but the most obvious is people calling out the specific behaviour that they are invoking or believe might be helpful in a discussion. For example, I might ask someone to share their reasoning and intent and then move on to jointly designing the next steps.