Magic & Math with Cards

Lecture 15 · Performance

One rank, one suit, three revelations

Video in production

This lecture is still face down. Its script is written; filming and animation are under way.

Meanwhile, play the trick

What you will learn

Perform and explain Wohl’s three-person cyclic-deck effect using two partial clues.

The trick in this lecture One Rank, One Suit Name one card's value and the next card's suit. All three cards are named. Play the trick

Before this lecture

Ideas you will use

  • Cyclic order and straight cuts
  • Rank and suit identity

In this lecture

An outline of the lecture, scene by scene, with the statements that appear on screen. It follows the draft script, so details may change in production.

  1. Introduce three different information budgets

    At the table
    • Place 1: value
    • Place 2: suit
    • Place 3: no clue

  2. Collect rank and next suit without ambiguity

    At the table
    • Only two clues are collected
    • Rank of first; suit of second

  3. Reveal and move to open method

    At the table
    • Ronald Wohl’s cyclic-deck effect
    • Prepared does not mean every choice is fixed
    • Worked example: 8, hearts

  4. Reveal two repeating cycles

    • Rank period 13
    • Suit period 4
    • First joint return: lcm(13,4)=52

  5. Decode complete sample from predecessor suit

    • Second suit H →first suit C
    • 8C →KH →3S
    • Backward once; then forward

  6. Compare information counting with compatibility

    • 13×4=52 clue pairs
    • A count is not an arrangement
    • Capacity →construction →execution

  7. Rehearse actual procedure and deterministic second example

    • Q +next suit C →QD,4C, AH
    • Keep three selections separate
    • Rank names avoid numerical ambiguity

  8. Companion tasks and transfer to general coding

    • Decode the joint state
    • Explain each successor
    • Challenge: repair a damaged protocol

Companion interactive

Identify three cards from rank 1 and suit 2.

The trick page is this lecture’s companion: be the spectator, lift the curtain to step through why it works, try the challenge, then learn the handling.

Open One Rank, One Suit

Sources

How these sources were used
  • Persi Diaconis and Ron Graham, Magical Mathematics: Ronald Wohl effect and Eight Kings/CHa Se D stack; suits and ranks do not require a secret peek.