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Comment by Imnimo | Hacker News Reader

I used to play a MUD (a text-based proto-MMORPG). It had a command to let you flip a coin. After many years, a player felt like they were noticing more tails than heads. They ran some experiments, and eventually an administrator checked the code - it turned out there was an off-by-one error in the coin flip logic (which inexplicably relied on generating a random number 1-10), such that coin flips had been 40/60 since the release of the game, and no one had noticed for over a decade.

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My favorite baffling RNG bias was in the game Maplestory. It always seemed like RNG was extremely "clumpy". For example, critical hits would frequently come in bursts - you might get around 5 seconds of non-stop crits.

The crafting system was heavily chance based. You'd get say 7 attempts to augment a piece of gear, using 'scrolls' that had a certain percentage chance of succeeding. The lower the chance, the bigger the improvement to your gear. So a pair of gloves that had 7 successfully applied +attack 10% scrolls would be incredibly valuable. The superstitious method to crafting (which, anecdotally, worked incredibly well) was to get a ton of gloves and a ton of scrolls, and apply one scroll to one pair of gloves and throw them away if it failed. Once you had a single success, you would apply the scrolls as quickly as possible to try and ride the RNG wave. In my experience, this would very frequently result in getting 3+ successes in a row.

Many games implemented strange RNG mechanics like this to game psychology. Eastern 2D RPGs were notorious for this, since they relied heavily on MTX.

I'd love to see the code!

A funny story of a miscommunication about randomness in the real world, there was a miniatures game called Heroclix in the early 2000s. They apparently communicated with the factory that was making them in China that they wanted 5% of the miniatures printed to be the ultra rare ones.

So the Chinese happily obliged. The first 5% of the run was nothing but ultra rare miniatures and none of the remaining 95% printed had any ultra rates. The first people to buy boxes were very happy!

Huh. I once wrote a MUD client that didn't have an obviously documented way to quit and got email for years after complaining that I had "made the application too addictive".

Discworld MUD, if you flip a coin in a room where to many spells have been cast it might turn into a caterpillar.

30/60 maybe?

EDIT: probably not after reading the comments. I thought I was smart ;)

Either could be the case - if it was generating numbers from 1-9 instead of 1-10 30/60, if it was comparing <= 5 vs <5 it could be 40/60

Yeah, I'm almost certain it was the latter. I remember they shared the code snippet, but that was in 2007 and the game's forums have been replaced since then. I did find a recounting of it:

https://forums.achaea.com/discussion/comment/249213/#Comment...

(and the associated quest to discover the easter egg of a coin landing on its edge with 1 in a million odds that was added when the bug was fixed)

40/50 probably. One of the 10 numbers never showed up. 1-5 tails, 6-9 (should be 10) heads.

I ran into the same thing when I made a custom dice roller for Settlers of Catan. Rand(1, 6) never produced a 6, which you could tell if you inspected the comments closely, but still feels counter-intuitive to me.

Our Catan set has noticeably nonuniform dice. They roll high numbers much more frequently than low numbers; presumably bc the high-numbered sides weigh less (?). We haven't buckled down and done the science but it definitely tilts the game play, to the extent that we're considering swapping them out for new dice.

(or this could just be Catan Crankiness (TM), but we've all noticed it quite a bit...)

On the subject of Catan and dice:

https://www.chiark.greenend.org.uk/~sgtatham/dice/

That is a good example of an over engineered solution. The game already has a far simpler way to make it easier for all players to get started, regardless of how many turns you play. It might be from one of the expansions, but we use it in the normal game as well.

The "friendly robber" rule states that you are not allowed to place the robber on any tile that has a village of a player that does not have any points yet.

Which MUD was this?

Achaea

What are the odds wow

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