Saved by Rolling Rock

Statue of Sisyphus rolling a rock

Our friend Baquies asked a question that I like very much: my OED Traps Digest has a 10' diameter rolling rock trap, which I basically lifted from Moldvay's Lost City adventure (module B4, area 39), and he probably swiped it from Raiders of the Lost Ark the prior year. 

Now, I stipulate that after the boulder comes to a rest, it can be pushed aside 1 in 6 by a normal man. Is that reasonable?

Looking at the Rockhound Resource website, one of the examples in a table there includes a rock that's "Car sized | ~10 ft" weighing in at at about 86,500 pounds (and I double-checked the calculation: assumes about granite density).

An answer to a Quora question (by Charles Collins -- no relation, I assume) says that the optimal coefficient of rolling resistance on level ground is 0.10 (for a car with inflated tires, or a plane bearing). For our rock this gives a critical force of 86,500 × 0.010 = 865 pounds.

Can a man push that much? That's something I suppose a gym could answer. I think it's pretty common to bench press 100 pounds or so. An answer on Reddit here says regarding a leg-press machine, "People can easily hit up to 400-600 pounds or more on these machines, I would design for a force of 1000 pounds to have some safety factor built in."

So maybe we should dial down our rock a little bit, say to about an 8' diameter -- thereby letting it roll a bit more freely down our standard corridor, and also reducing the weight by half, to about 44,300 pounds, with a critical rolling force of about 443 pounds. This seems to put it squarely in the range that a fit man could roll, if he had his back against one wall, and pushed with both legs.

(And our friend Seeker points out that the easiest rock to carve for this purpose would be limestone, so let's say that's the material, which increases the weight a small amount, i.e., by 2% or so.)

What are your thoughts on that? Will it make Sisyphus happy?


OED House Rules v.1.0.7

OED Player's Rules Cover

Presenting the state of the OED House Rules for 2022: we've bumped up both the Player's and Judge's rules documents to version 1.0.7. Some of the more important edits you'll find there:

Player's Rules

  • Combat Feats have been reworked & rebalanced for a better overall distribution. (In particular, Rapid Attack is no longer the hands-down best choice.)
  • Sweep Attacks are noted as a universal ability for all Fighters, as opposed to the ambiguous state it was previously left in (and the Cleave feat consequently removed). See numerous analytic posts in which we researched this issue in 2021; in short, if you're going to play with O/AD&D listed large numbers appearing for low-level monsters, then players need this ability to stay competitive.

Judge's Rules

  • Mechanics based on a d6 roll have been synchronized to follow a low-roll for success model, following the majority of the instances in the LBBs. See here for the analysis on that.  
  • Slime/ooze monster mechanics were edited to match results of recent polls we ran (to be presented in the near future).

Monster Database

  • At least as important as any of the above, we've recently significantly expanded the Arena simulator program to include common wizard spells, magic-using and exotic monster types, etc. EHD (Equivalent Hit Dice values) have been modified to reflect that; basic monsters (giant-types, etc.) mostly stayed the same, while some outliers had large changes (e.g., vampires, golems, etc.). 
  • All monsters now have a justified EHD listings (previously some special or spell-using types were left with a null entry). 
  • The database has been expanded with more monsters from the OD&D supplements (now over 200 listed!).
  • Quick copy-paste stat blocks are now at the OEDGames site; the complete database in spreadsheet format is kept in the repository at Github.

We'll plan to post more updates and reflections on lessons from that recent simulator work in the coming weeks. Big thanks to the Wandering DMs patrons for kicking around and giving invaluable feedback and motivation on most of these issues. If you play around with these rules, tell us how they play for you! 

OED House Rules v.1.0.7 at OED Games