December 7, 2025
Roll wars: clock vs common sense
A two-person method to simulate die rolls
Two friends reinvent dice with a “clock trick”—and the internet rolls its eyes
TLDR: Two travelers proposed a two-person “clock” trick for making fake dice rolls. Commenters clapped back, calling it overcomplicated and self-defeating, and suggested easier fixes like adding numbers mod n, using a watch’s second hand, or nerdy math tricks—sparking a lively debate about bias and DIY randomness.
Stranded in Xi’an with dead phones, two friends tried to save their DIY D&D session by inventing a two-person “clock” trick to fake a die roll—pick numbers, measure the gap, pretend it’s random. The blog swears it’s fair “in ideal conditions,” but that’s exactly where the comment section detonates. The top vibe: cute idea, wildly overcomplicated.
One camp says just add the numbers and take the remainder. “A + B mod n seems much easier,” snaps a commenter, while another points out the paradox: the method admits humans are bad at unbiased choices… then requires unbiased choices for fairness. The internet’s eyebrow collectively shoots up. Others pile on with old-school hacks—“glance at your watch’s second hand, done”—and a math-goblin chimed in with a chaotic alternative: add your numbers, take the square root, mine the decimal digits for “randomness,” and, as they put it, “good luck proving it.”
There’s also laughter at the idea of “conflict of interest” magically de-biasing people, and side-eye at the edge cases where the clock trick doesn’t cleanly map to standard dice. Fans applaud the creativity; skeptics say it’s reinventing a wheel with extra spokes. Either way, the real roll here wasn’t the number—it was the drama. For more, see random number generation.
Key Points
- •A two-person RNG method is proposed using angles on a unit circle, computing and normalizing angular difference to produce a [0,1) value.
- •If the angular difference exceeds π, it is adjusted (δ → δ − π) to keep the RNG within [0,1).
- •A discretized version maps the circle to a 12-hour clock; two participants simultaneously pick integers in [0,12).
- •The angular distance between the two clock choices is used to simulate a six-sided die roll.
- •Under unbiased choices and rotational invariance, distances 1–5 have equal probability (matching a fair die), while 0 and 6 deviate (distance 6 shown as 1/12).