1. In advance, hammer one nail partially (vertically) into the centre of the block of wood, ie approx 10mm.
2. Lay the other 12 nails next to the block of wood.
3. Challenge your group to balance all 12 nails on top of the vertical nail.
4. Announce that all nails (as a group) must be balanced on top of the nail at the same time.
5. None of the 12 nails is permitted to touch the wood (or any other apparatus.)
6. Allow up to 30+ minutes to solve the problem.
7. Encourage innovation, especially those ideas that reflect thoughts of engineering.

Thirty-plus years on, the solution to this team puzzle still fascinates me. So simple, yet so hard. Full disclosure – I was never able to solve the mystery, I had to have it shown to me.

Grab the required equipment from your local hardware store, or you may have the bits kicking around in your shed. Importantly, ensure that all 13 nails are identical.

Knock one of the nails (featuring a flat top or bullet head) into the centre of the block of wood about 10mm or so. Check that the nail is fastened firmly into the wood, and then lay the remainder of the nails next to the wooden block.

With your group peering at this innocent collection of building materials, introduce the challenge – to balance all 12 nails on top of the single vertical nail all at the same time.

At this juncture, you can expect a few quizzical looks, so I sometimes take one nail and lay it horizontally on top of the vertical nail. Depending on the width of the top of the vertical nail, I may be able to balance two nails, laid side by side.

Go no further, it will be clear to everyone that there are still 10 more nails to balance.

Having provided a brief glimpse into one possible strategy, be sure to announce that this demonstration does not suggest that this method is the way to solve the problem. Hint – while in theory, this strategy can work – stacking two perpendicular nails side-by-side on top of two other nails, and repeating 6 times rarely ever does.

When ready, dispense with any questions and then step back.

Expect lots of nails crashing to the ground on many occasions and groans of frustration, especially as time progresses.

Look to the Leadership Tips tab for ways to manage bouts of frustration from time to time.

Need to See the Solution? 

As they say, seeing is believing. If you or your group can’t work out the solution, contact me, and I’ll email you an image featuring the most common solution.

Don’t skimp on size. The bigger (longer) the nails, the better. Large nails not only make the solution easier, but the result is so much more satisfying.

It is not uncommon that most people/groups will fail to discover a solution. Encourage as much as you can, and when your group starts to fluster, inspire them with thoughts of engineering principles. For example, ask your group to consider how a wine bottle could possibly balance when the throat of the bottle is poked into a piece of wood (see image at right.)

Got a large group? Prepare multiple sets of wooden blocks and nails. As this is a very tactile initiative, invite only 2 to 4 people (max) to form teams around each set.

This exercise is also known as Hard as Nails, as described by Karl Rohnke in his book FUNN n Games.

When you see the solution, you’ll understand why it’s called the “Porcupine” Progression. Indeed, you may choose to share the fact that a popular solution resembles one of the features of a porcupine.

You could integrate Porcupine Progression as part of a well-designed SEL program to develop your group’s ability to manage their emotions, thoughts and behaviours effectively in different situations and to achieve goals.

Specifically, this activity ample offers opportunities to explore and practice the following social & interpersonal skills:

Self-Awareness

• Identifying Emotions
• Linking Feelings, Values & Thoughts
• Having A Growth Mindset

Self-Management

• Controlling One’s Emotions
• Identifying & Managing Stress
• Demonstrating Self-Discipline & Self-Motivation
• Use Planning & Organisational Skills

Social Awareness

• Taking Other’s Perspectives
• Recognising Strengths In Others
• Respecting Others

Relationship Skills

• Communicate & Listen Effectively
• Work Collaboratively
• Showing Leadership
• Resolving Conflict Constructively

Responsible Decision-Making

• Demonstrating Curiosity & Open-Mindedness
• Identifying Problems
• Identifying Solutions
• Promoting Personal & Collective Well-Being

You can learn more about SEL and how it can support character education here.

There is no specific health & wellness perspective to this activity other than promoting the benefits to one’s well-being of working successfully with others to solve a problem.

In a small way, you could argue that the focus and patience required to interact and engage with others to solve the problem may speak to the benefits of developing a set of supportive and healthy behavioural norms in advance. Or, if not, you could use these less-than-desired interactions or outcomes to explore what sorts of behaviours your group would prefer to see.

For example, you could invite your group to reflect on the level of patience and resilience demonstrated during the activity and relate this to a set of observed impacts and outcomes.

• Larger Than Life: Use long lengths of PVC pipe (each with a T-section glued to one end) instead of nails. Fasten another PVC pipe or metal spike in the ground and challenge your group to complete the challenge (as described above) but bigger. See page 105 of FUNN ‘n Games book by Karl Rohnke for an example.
• Take a look at Arrowheads Puzzle, Two by Four and Rope House to enjoy three more very challenging team-based puzzles.

The solution to this next group initiative still fascinates me 30+ years after it was first introduced to me. When you look at the props involved, it’s hard to imagine the challenge can be solved, but I assure you it can…

If you enjoy engineering or building things, then I think you’ll enjoy this next puzzle. You will need to pool your collective ingenuity to solve this team challenge…

When things seem impossible, how do you react? How do others react around you? I’m going to present a really unique challenge to you shortly that will challenge you to find a solution, but I assure you that it does…

Coupled with one or more reflection strategies, here are some sample questions you could use to process your group’s experience after playing this fascinating team puzzle:

• At what point did you feel that you were getting frustrated?
• Why were you frustrated?
• Did you employ any strategies that helped you cope with the frustration?
• What helped your group discover a solution that worked?
• Once you saw the solution, what did you think?
• Could it be possible that other intractable problems in your life and work have a solution too, ie but you can’t see it yet?