Marshmallow Challenge: Rules, Variations, and Team-Building Lessons

Introduction

Four people stand around a table.

On the table: a handful of dry spaghetti, some tape, a piece of string, and one lonely marshmallow.

“18 minutes. Build the tallest free-standing tower you can. The marshmallow has to go on top.”

At first, everyone talks.

Someone waves their hands, explaining a “perfect” design.

Someone starts taping spaghetti together.

Someone carefully lifts the marshmallow onto the top…

The tower wobbles, leans, and collapses.

People shout, laugh, and rush to fix it before the timer hits zero.

That’s the Marshmallow Challenge.

It looks like a silly tower-building game, but in those 18 minutes you can see a lot:

how your team plans, who grabs the materials, who leads, who stays quiet, and whether people prefer long discussions or quick experiments. It’s a fast, low-risk way to watch your team’s real habits show up on the table.

Research from Tom Wujec’s TED talk “Build a Tower, Build a Team” and his original Marshmallow Challenge slide deck shows that, across dozens of workshops, the average team builds a tower of about 20 inches (around 50 cm). Business school students typically come in well below that, at roughly 10 inches, while kindergarten teams consistently beat the average with towers in the mid-20-inch range. Architect and engineer teams go higher still, often approaching 30 inches or more, and CEO teams sit just above the overall average. When CEOs work with their executive assistants, average tower height jumps to around 30 inches, highlighting how facilitation and coordination skills can dramatically improve performance. For a quick overview, you can also check the official Marshmallow Challenge site, which summarizes the exercise and its key lessons.

For you, the value is simple: with cheap materials and a tight deadline, people get a real taste of:

• Design thinking in action (build → test → adjust)

• Team collaboration (roles, communication, decision-making)

• Fast experimentation (it’s normal if the first tower collapses)

By the end of this guide, you’ll know:

• What the Marshmallow Challenge is and the exact rules

• Which materials to prepare and how many people per team

• How to run the activity step by step in a workshop or classroom

• Easy variations for kids, students, and professional teams

• Debrief questions and key lessons you can bring back to real projects

What Is the Marshmallow Challenge? Rules and Materials

1.1 Objective and basic rules

At its core, the Marshmallow Challenge is a team-building game where small groups try to build the tallest free-standing structure they can in a short time. The twist: a whole marshmallow has to sit on the very top when time is up.

If I had to sum up the objective in one line, it would be:

Build the tallest structure you can, using only the given materials, with a marshmallow on top that can stand on its own at the end of the timer.

The classic rules most facilitators use are very simple:

• You work in teams of 3–5 people.

• Each team gets the same kit of materials (no trading between teams).

• You have 18 minutes (some people use 20, but 18 is the famous version).

• Your structure must be free-standing – it cannot lean on people, walls, chairs, or the ceiling.

• The entire marshmallow must be on the top. You can’t cut it in half or “hide” parts of it inside the structure.

• You may break the spaghetti and cut the tape and string into smaller pieces if you want.

The team with the tallest valid tower at the end wins. “Valid” simply means: marshmallow on top, hands off, still standing after a few seconds.

1.2 Standard materials list

One reason I like this game is that you don’t need fancy props. A supermarket and a stationery drawer are enough.

A standard kit per team looks like this:

• 20 sticks of dry spaghetti

• 1 meter / 1 yard of tape (masking tape or painter’s tape is easiest)

• 1 meter / 1 yard of string

• 1 marshmallow

Nice-to-have extras:

• Scissors (1 per team, or shared on a central table) for cutting tape and string

• A paper bag or envelope to keep each team’s kit together until you say “go”

For planning:

• Aim for 3–5 people per team.

• Prepare one full kit per team, and don’t add more materials halfway through – the constraint is part of the game.

1.3 Who this activity is for

This isn’t just a kids’ craft. I’ve seen the Marshmallow Challenge work in a lot of different settings:

• Corporate team-building & offsites

  Great as an energizer or opening activity. People move, talk, and laugh, but you also get a quick snapshot of how they make decisions under time pressure.

• Innovation, design thinking, and agile workshops

  Perfect before you talk about prototypes or sprints. Instead of listening to theory, people feel what “build → test → adjust” actually means – in their hands, not just in slides.

• High school and university classrooms

  Fits naturally into STEM, engineering, business, and design courses. It turns abstract ideas like “constraints”, “assumptions”, and “iteration” into something very concrete.

• Coaches, trainers, and facilitators

  Useful any time you want to surface team roles, communication patterns, or leadership styles quickly, without doing a heavy personality test or long assessment.

If your group can stand around a table and hold spaghetti, they’re a good fit. You just adjust the framing and debrief depending on the age and context.

1.4 Not just a kids’ game: why it’s powerful

For me, the Marshmallow Challenge is worth running not because of who builds the tallest tower, but because of what it reveals in 18 minutes. As you saw in the intro, kids and professionals don’t always perform the way you’d expect – and that’s the interesting part.

When I look across workshops and Tom Wujec’s classic data, three things stand out:

• The marshmallow = hidden assumptions.

  Most teams quietly assume “the marshmallow is light, it’ll be fine.” They only test it at the very end, and the whole structure collapses. In real projects, that marshmallow might be your pricing, your tech stack, or your “of course users will love this” belief that nobody validates early.

• Winners prototype early, not perfectly.

  The best teams don’t wait. They put the marshmallow on top early, watch things fail, and adjust. They get several learning loops in the same 18 minutes while other teams are still debating the perfect design.

• Team habits become visible.

  You can literally watch how people react to uncertainty: Who grabs control? Who steps back? Who quietly fixes things? Who never gets heard? Those patterns look surprisingly similar to how the same group behaves on real projects.

That’s why I treat the Marshmallow Challenge as a high-value team-building game: cheap materials, short time, but a very sharp mirror of how your team handles assumptions, iteration, and collaboration.

How to Run the Marshmallow Challenge (Step-by-Step Guide)

2.1 Before you start: room, kits, and timing

If you set this part up well, the activity almost runs itself. Here’s how I usually do it.

Room setup

• One table per team (or clearly marked space on a large table).

• Enough room for people to stand and walk around without bumping into each other.

• A wall or screen where you can show a countdown timer and the basic rules.

Materials prep

• Decide how many teams you want:

  • Small session: 3–4 teams

  • Medium session: 5–8 teams

  • Large session: 9+ teams

• Prepare one complete kit per team (spaghetti, tape, string, marshmallow).

• Put each kit into a paper bag or envelope so everyone starts from the same “reveal”.

• Keep a few spare marshmallows just in case one falls on the floor.

Time plan for the whole activity

You don’t need an exact script, but this structure works well:

• Intro & rules: 3–5 minutes

• Build time: 18 minutes

• Show & measure: 5–10 minutes

• Debrief & lessons: 15–20 minutes

If you’re tight on time, you can shrink the debrief. Try not to cut the 18-minute build too much—that time pressure is part of the experience.

2.2 What to say to the group (simple script)

You don’t need a long speech. In fact, shorter is better. People understand the game faster when you keep it tight.

You can put something like this on a slide and read it out:

“You’re going to do the Marshmallow Challenge.
In teams of 3–5, you’ll have 18 minutes to build the tallest free-standing structure you can.
You can only use the spaghetti, tape, string, and marshmallow in your kit.
When time is up, the structure must stand on its own, and the whole marshmallow must be on top.”

Then add the key do / don’t rules:

• You may break the spaghetti.

• You may cut the tape and string into smaller pieces.

• You may not tape anything to the floor, wall, ceiling, or furniture.

• The marshmallow must stay whole and sit on the very top.

Finish with:

“Any questions before we start?
If one team asks a question, I’ll answer it for everyone.”

The important part:

• Answer questions consistently for all teams.

• Don’t keep adding new rules mid-game; it frustrates people and confuses the results.

2.3 Timing, measuring, and scoring

Once everyone understands the rules, it’s all about clear timing and a fair way to measure.

During the 18 minutes

• Use a visible countdown timer (phone mirrored to screen, online timer, or slide).

• Give short time updates, for example:

  • “You have 10 minutes left.”

  • “5 minutes left.”

  • “Last 60 seconds—hands will be off the structure when the timer hits zero.”

When time is up

1. Ask everyone to step back from their structures. No touching after the timer ends.

2. Check that the marshmallow is on top and the structure is free-standing.

3. Make sure it stands on its own for 3–5 seconds. If it falls immediately, it doesn’t count.

4. Measure from the table surface to the top of the marshmallow using a tape measure or ruler.

5. Record each team’s height and announce the winning tower.

You can also add small “bonus” awards to keep it fun:

• Tallest valid structure

• Most creative design

• Most stable or “earthquake-proof” structure

For planning sessions of different sizes, you can use this rough guide:

You can copy this table straight into your agenda or workshop notes.

2.4 Facilitation tips: what you should (and shouldn’t) do

Your role isn’t to help them “win” the game. Your role is to protect the constraints and watch how people behave inside them.

What you can do:

• Keep an eye on time and give clear reminders.

• Encourage teams to start building early if they seem stuck in endless discussion.

• Walk around and observe:

  • Are they talking forever before touching the materials?

  • Does one person take over as leader?

  • Is anyone quiet the whole time?

  • Do they try multiple versions or stick to one design?

What you should avoid:

• Don’t suggest specific structures (“Try a tripod”, “Make triangles”).

• Don’t tell them the “secret” that the marshmallow is heavier than they think.

• Don’t change rules halfway (“Oh, and also you can’t…”).

I like to jot down a few quick notes while I walk:

• “Team A: long planning, marshmallow only on at the end.”

• “Team B: three small prototypes, marshmallow tested early.”

• “Team C: one strong voice, others ignored.”

These small observations become gold in the debrief. Instead of generic advice, you can say things like:

“You might have noticed your team only put the marshmallow on in the last 30 seconds,” and people instantly connect the game to how they run real projects.

How to Win the Marshmallow Challenge (Player Tips & Strategy)

If you want to win the Marshmallow Challenge, don’t just “play” it. Treat it like a tiny project with a deadline: align fast → prototype early → protect what works.

1. Before the timer starts: get the basics right

You only need 60–90 seconds before building, but those seconds matter.

• Say the goal out loud once.

  “Tallest free-standing tower, marshmallow on top, 18 minutes.”

  Saying it clearly once keeps people from quietly forgetting “free-standing” or the marshmallow when things get busy.

• Agree on one simple idea, not a perfect blueprint.

  For example: “Wide base, triangle-ish frame, we test the marshmallow early.”

  One shared direction beats three competing “perfect” designs every time.

• Keep roles light.

  One person watches the timer.

  One person watches stability (“this side is bending”).

  Everyone builds, holds, or cuts tape.

  Heavy labels like “architect” or “leader” usually slow people down in an 18-minute game.

2. While building: prototype fast and use good structure

This is where most teams quietly win or quietly lose.

• Get “Version 1” up fast.

  Aim to have some tower standing in the first 3–5 minutes, even if it’s short and ugly.

  A rough Version 1 is worth more than a beautiful idea that never gets built.

• Put the marshmallow on earlier than feels safe.

  Don’t wait until the last 30 seconds.

  If the structure collapses when the marshmallow goes on, that’s not failure—that’s feedback. You’ve just learned how strong the base really is while there’s still time to fix it.

  Personally, I’d rather “pay” for two early collapses than discover the problem at the final beep.

• Use a wide base and triangles.

  Winning towers usually share three things:

  • A wide base

  • Diagonal pieces that form triangles

  • The marshmallow gently balanced at the top

    Straight, skinny columns with no bracing almost always fold as soon as the marshmallow goes on.

• Talk in short, concrete sentences.

  While building, use clear, simple comments like:

  • “This joint is bending.”

  • “Let’s make this base piece longer.”

  • “We need one more cross-brace here.”

    Less speech, more movement. Every long monologue is tape and spaghetti not moving.

3. The last 3 minutes: protect the win

This is where a lot of teams throw away a good tower.

• Stop big redesigns.

  If the tower is standing with the marshmallow on top, your main job now is: don’t kill it.

  Add small supports. Don’t rip out whole sections or change the entire design.

• Add height in tiny bites, not huge leaps.

  If you really want a bit more height, add short pieces of spaghetti at the top, one at a time, and test after each change.

  The “one huge last-minute stick” is almost always the “we lost in the last 10 seconds” story.

• Do a “hands-off rehearsal”.

  About 30–40 seconds before the end, have everyone take their hands off like it’s the final moment.

  • If it falls, you still have a little time to fix something.

  • If it stands, don’t touch it again unless you’re absolutely sure.

    I’ve seen this tiny habit save more winning towers than any clever structural trick.

• Let one person call “stop”.

  Agree that one teammate watches the clock and has permission to say:

  “We stop here. No more changes.”

  That one sentence often protects a winning tower from a last-second disaster.

4. After the game: upgrade yourself, not just the tower

When it’s over, don’t waste energy blaming whoever “ruined” the structure. Use the game to learn something about your default style.

Ask yourself one question:

“If we played again, what would I do differently in the first 5 minutes?”

Maybe the answer is:

• “Speak up earlier instead of waiting.”

• “Test the marshmallow sooner instead of over-explaining.”

• “Help connect other people’s ideas instead of pushing my own.”

Pick just one of those upgrades and bring it into your next real project.

If you do that, you’ve already won more than a marshmallow game—you’ve turned 18 minutes of spaghetti chaos into a small but real improvement in how you work with other people.

Marshmallow Challenge Variations & Real-World Examples

3.1 Adjusting difficulty for kids vs. adults

When I tweak this game, I usually only change two things: time and how strict the rules feel.

For kids (elementary / middle school)

• Give a bit more time: 20–25 minutes instead of 18, so they’re not just fighting the clock.

• Keep rules ultra simple: “Tallest free-standing tower, marshmallow on top, don’t tape to walls.”

• Emphasise trying ideas and working together, not “who beat who”.

For adults (teams / leadership groups)

• Keep the classic 18 minutes and the standard kit.

• If you want more challenge, add one small twist, not ten:

  • “You only get 10 pieces of tape,” or

  • “Each person must touch the structure at some point,” or

  • “You must sketch at least one idea before building.”

• Use the same debrief questions, just framed in work language: “Where do we over-plan? Where do we avoid testing the ‘marshmallow’ early?”

3.2 Theme-based variants (innovation, communication, leadership)

You don’t need a whole new game for different training goals. A light reframe is often enough.

Innovation version

• Tell teams: “Quantity of ideas first, then pick one.”

• Optional constraint I like: everyone sketches one idea each in 60 seconds before anyone starts building. This forces variety before convergence.

Communication version

• Give each person 3 “talk tokens” (three times they’re allowed to speak).

• Once they’re out, they can only ask yes/no questions or build silently.

• Debrief: who chose their moments carefully, who burned all their tokens fast, who stepped back and listened.

Leadership version

• Hand out small, secret role cards:

  • “Push for decisions.”

  • “Ask quiet people what they think.”

  • “Say yes to ideas you normally dislike.”

• In the debrief, reveal roles and talk about which behaviours actually helped the team under time pressure.

3.3 Real stories from Reddit (clickable case studies)

Instead of more abstract “use cases”，here are real people actually running the Marshmallow Challenge, so your readers can click through and see how others frame it:

Had the most fascinating case study into our current crop of students this week

from r/Professors

Science-related icebreakers

from r/ScienceTeachers

Ice breaker ideas for 11th grade?

from r/ELATeachers

3.4 Remote and low-material alternatives (short and practical)

Remote / hybrid teams

• Ask each small group to use whatever they have on their desk (books, pens, tape) to build a free-standing “tower with a top object” while on video.

• Screen-share a countdown timer.

• Have each team quickly show height and stability on camera, then jump straight into the same debrief questions.

Low-material version

If spaghetti and marshmallows are hard to find, keep the core structure of the game and swap materials:

• Paper + tape + one heavy-ish item (eraser, marker, small ball) as the “marshmallow”.

• Plastic cups + index cards + one book on top.

• LEGO / blocks for younger kids, still with a “top piece must stand on top at the end” rule.

Debrief & Key Lessons from the Marshmallow Challenge

4.1 Reflection questions that actually get people talking

You don’t need a long questionnaire. A small set of sharp, open questions is enough.

I like to split them into process and teamwork.

Process-focused questions (what you did)

1. How did you decide on your first design?

2. When did you first put the marshmallow on top? (Early, middle, or at the end?)

3. What changed in your plan once you started building?

4. If you had 5 more minutes, what would you have tried?

Teamwork-focused questions (how you worked together)

5. What roles appeared in your team (planner, builder, timekeeper, joker, fixer…)?

6. Who did most of the talking, and who did most of the building?

7. When there was disagreement, how did you resolve it?

8. If you did this again with the same people, what would you change about how you work together?

You can run these as a whole-group discussion or give each team 2–3 questions to discuss and then share one insight back.

4.2 Iteration & rapid prototyping

One core lesson is brutally simple: teams that prototype early beat teams that chase the perfect plan.

Tom Wujec and others note that many adults treat the marshmallow as “light and easy”, build one tall structure, and only test the marshmallow in the final seconds—then everything collapses. In contrast, high-performing teams (often kids or design/engineering groups) build small versions, test with the marshmallow, and refine several times in the same 18 minutes.

A nice debrief move is to ask:

• “Did we act like a ‘one big bet’ team or a ‘many small bets’ team?”

• “Where, in our real work, do we also put the ‘marshmallow’ on only at the end?”

Linking that directly to product launches, campaigns, or projects makes the lesson stick.

4.3 Team roles & communication patterns

The game is also a fast X-ray of how your team behaves under pressure.

From multiple workshop write-ups, you see the same patterns: effective teams often have someone quietly facilitating—keeping time in mind, inviting quieter voices, and nudging the group to test early—rather than just a loud “boss”.

Good questions here:

• Who took initiative without being asked?

• Was leadership shared, or did one person drive everything?

• Did anyone’s idea get ignored until it was too late?

Then connect it:

• “Does this look like how we start real projects or meetings?”

• “Which behaviours from this tower-building round would we want to see again at work—and which ones should we leave here?”

Even a short, honest conversation here can surface things people normally tiptoe around.

4.4 Bringing the lessons back to real work

To keep this from being “just a fun game”, I like to land on 2–3 concrete habits people can take away. The literature around the Marshmallow Challenge and rapid prototyping lines up on very similar points.

You can frame it like this:

• Prototype earlier.

  For new products, features, or processes: build a small, ugly version early—like your first “wobbly tower”—and test the risky part (your “marshmallow”) as soon as possible.

• Schedule tiny experiments, not just big plans.

  At the start of a project, ask: “What’s our first 1–2 day experiment?” instead of “What’s our 30-page plan?” Make experimentation part of the schedule, not an afterthought.

• Make space for quiet voices.

  In the challenge, the best ideas often come from the person who talks least. In real meetings, you can copy this by pausing and asking: “We’ve heard a lot from X and Y—what do the rest of you see?”

You can even close the debrief with a quick round where each person shares one sentence:

“One thing I’ll do differently in our next project because of this game is…”

If every person leaves with a small, specific change, those 18 minutes of spaghetti and marshmallows have already paid for themselves.

Ready to Try It with Your Group?

The Marshmallow Challenge looks like a silly tower game, but it gives you a fast, honest snapshot of how people plan, talk, and handle surprises together. In 18 minutes, you can see real habits around design thinking, teamwork, and testing risky assumptions.

You don’t need anything extra now—this page already gives you the rules, materials, step-by-step flow, and debrief questions. Pick a small group, set a timer for 18 minutes, and run a test round this week. Start simple, keep the rules clear, and spend a few minutes afterwards asking what people noticed about the way they worked.

If it lands well, you can make it a regular part of your workshops or classes, or mix it with other activities on ice breaker games—for example a more physical team puzzle like Human Knot, a communication game like Telephone Charades, or a quick warm-up like Zip Zap Zop.

Try it once, see what your team learns, and then decide how you want to use it next time.