Paper Cantilever

How to play

The short version

Build with identical playing cards at the edge of a table. Each turn add or remove one card. After twelve turns, measure how far your structure reaches beyond the edge without a hand holding it.

Set up safely

Recommended ages 8+, with adult help choosing a suitable surface. Use twelve ordinary identical-sized playing cards, one spare measuring card, paper and a pencil. Use a stable, dry, uncluttered table with a straight edge; play seated. Clear the floor below. Cards are the only building material: no books, weights, tape, liquids or sharp objects. Do not climb, lean on the edge or try to catch falling cards. If the table edge is rounded or cards slide without deliberate movement, choose another safe surface.

Mark eight equal divisions along the spare card's long edge; this is your ruler. Call one division a unit. Put the twelve building cards in a supply on the table. Choose a starting player. Play three builds of twelve turns each, passing clockwise. Each build starts empty. Start the next build with the person after the previous build's starting player.

A turn

1. Choose one supply card and place it anywhere touching the table or existing cards; or remove one existing card to the supply. You may use two hands on that one card. Existing cards cannot deliberately be lifted, slid, held down or repositioned. Incidental tiny shifts caused by contact are allowed; pushing an existing card into a new position on purpose is not.
2. Release everything and count slowly aloud to three. Cards must support themselves. You may discuss the next move freely, but only the current player touches the build.
3. If any building card falls to the floor, or the structure needs a hand to stop it falling, the build ends immediately. Otherwise record the best stable reach achieved so far, then pass the turn.

Cards may lie flat or at angles, but cannot be folded, cut, bent deliberately, wedged into table gaps or attached to anything. The table surface is the only outside support. You may remove a card even if the supply is empty. With no legal safe move, pass; it still uses one of the twelve turns. The measuring card never supports the structure.

Measure and score

After a successful turn, look straight down. Measure perpendicular to the table edge, from the edge to the furthest projecting part of any building card. Use the marked spare card beside the build, without touching it or reaching under an unstable stack. Count complete units only; a reach of 3½ units scores 3. If direct measurement would disturb the structure, mark the endpoint on a separate paper guide beside it first. Settle uncertain fractions downward.

Each build scores its greatest stable reach, even if a later turn collapses it. A build also ends after turn twelve; clear it by hand only after recording its score. Add all three scores for your team total. There is no individual winner. On your next session, beat your own total with the same card type, edge and challenge; an equal total ties your previous best. There is no tested difficulty benchmark.

Worked example

A first card projects two full units and stays still for the count, so the team records 2. A later card laid mostly on the table provides support without increasing the reach. The next card takes the tip to 3½ units: record a best of 3. A later collapse ends this build, but its score remains 3.

Replay challenges

First use Open Build for all three attempts. For a new session, choose one challenge and use it throughout: Open Build uses all twelve cards and either action freely; Short Supply provides only six building cards, still with twelve turns, making removal important; One Rescue provides twelve cards, but the team may remove only one card during each build. These totals are different records, not directly comparable. Change who starts and test a new support plan each build.

Phone, print and access

Keep the rules on a shared phone; only the homemade measuring card and a turn counter need marking. Printing is optional. A player who cannot handle cards may direct a willing partner's placement on their turn; the same one-card rules apply. There is no speed requirement.

Original Round & Revel challenge format built around card counterbalance. Not human-playtested; stability varies by cards and surface. The 10–20 minute estimate is provisional.

Printable materials

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What you need

• Twelve playing cards of the same size and stock, plus one spare card for measuring. Any faces are fine.
• A pencil, paper and a stable clear table with a straight edge.

Make the measuring card

Divide its long edge into eight equal segments. You can fold a separate paper strip in half three times and transfer the eight divisions; do not fold building cards. Label the marks 0 through 8. One segment is one scoring unit.

Team record

Challenge / Card type / Build 1 best / Build 2 best / Build 3 best / Total. For each build, cross off turn numbers 1–12. In One Rescue, also draw one removal box and cross it off when used.