Impromptu Collective Force by Thomas P. O’Brien

Impromptu Collective Force by Thomas P. O’Brien

Impromptu Collective Force (ICF) by Thomas P. O’Brien: Core Summary

Overview

ICF is a versatile card magic utility technique designed to collectively force a predetermined number (e.g., 12345, 1000) on an audience using their calculators, leveraging subtle calculator manipulation and phone handling tricks. It ensures all spectators unknowingly arrive at the target number through guided arithmetic steps, with applications in stage, parlour, and close-up magic.

Core Mechanic

1. Guided Arithmetic Setup: Instruct the audience to open their calculators and perform a series of dictated additions/subtractions with numbers provided by spectators (e.g., 2-digit + 3-digit numbers, then a 4-digit number).
2. Magician’s Hidden Adjustment: While pretending to verify “sync” with the audience, discreetly subtract the target number from the current total on a borrowed phone (typically an iPhone) to determine the “remainder” needed to reach the force number.
3. Forced “Random” Input: Guide a spectator to “blindly” type the remainder (via phone-screen遮挡, thumb swiping, or blocking input) to complete the calculation, resulting in the target number for all.

Key Features & Variations

• Basic vs. Advanced Versions:
  • Basic: Uses sequential additions with limited spectator choice.
  • Advanced: Allows spectators to choose operations (+, -, ×) and numbers, increasing perceived randomness, while the magician still controls the final remainder.
• Phone Compatibility:
  • iOS: Preferred for hidden input (e.g., blocking keypad with thumb swipes on modern iPhones; using +0× on older models with a Home button).
  • Android: Riskier due to visible calculation history; recommends TOXO method (+0× to mask prior inputs).
• Applications & Routines:
  • Force numbers linked to predictions (e.g., anniversary dates, ticket serials).
  • Integrate with marked cards, personal items (e.g., license numbers), or spectator-chosen bills for themed reveals.

Critical Techniques & Tips

• Discreet Manipulation: Use thumb swipes, phone rotation, or hand blocking to hide calculator adjustments.
• Spectator Management: Select cooperative participants for “blind typing”; avoid showing the final phone result to prevent exposure.
• Practice: Master phone handling (e.g., input blocking, quick subtraction) and remain calm to adapt if calculations go off-track (repeat the last step if needed).

Updates & Credits

• 2023 Bonus Handling: Added Michael Murray’s “screenshot cover” technique to further conceal the force.
• Influences: Inspired by Ian Pidgeon’s iTHUMP app, Mark Chandaue’s “Eskimos” effect, and Bob King’s TOXIC FORCE.

Purpose: ICF empowers magicians to create interactive, collective illusions with everyday devices, blending math, psychology, and technical skill for impactful, customizable routines.