Friday Encounter: Archimedes's Well

Here's a simple two-room puzzle designed to be slotted into a larger dungeon. This one is based on Archimedes's principle that an object displaces water equal to its mass, and attempts to simplify these physics for the sake of gameplay. Keep in mind that the intended solution to this puzzle may not be obvious unless your players are familiar with the theorem, although there are alternative solutions as well.

There should be one room in the dungeon with a large well in the center of the floor. The well drops a distance of about 200 feet before coming to standing water. Looking into the well reveals that a golden crown is floating atop the water, its surface reflecting light off any torches or lanterns, but it's far too deep to be reached from the surface.

A short distance away from the well is a pile of stones of various sizes. The third feature of the room is a door leading to the north (or whatever direction you want, it isn't important). On the wall opposite the door is a chipped, faded mural of a naked man holding his fists high in triumph, with the word "EUREKA" written over his head.

The intended solution to this puzzle is for the PCs to drop stones into the well, displacing enough water to lift the crown up to where it can be reached. They need to raise the water level a total of 200 feet in order to retrieve the crown.

However, they must do this without making too much noise, or they risk alerting an ogre who resides in the room to the north. When the PCs first enter the room, the ogre is asleep, and the sound of his snoring can be heard if one listens at the door. He's sleeping too soundly to be woken by normal conversation or footsteps. However, if the party makes any loud noises, or isn't careful in how they drop the stones, he will wake up and charge into the room.

If the PCs drop stones into the well, the water level rises by an amount of feet equal to the weight of the stone. They can use any combination of the stones to raise the crown, but every time they drop one, they must make a Stealth check; the ogre is alerted if the check fails.

The pile contains:

• Five 20-pound stones (DC 25; requires two hands to carry)
• Eight 15-pound stones (DC 20; requires two hands to carry)
• Ten 10-pound stones (DC 15)
• Fifteen 5-pound stones (DC 10)
• Twenty 1-pound stones (DC 5)

If the PCs wish to appraise the crown, a DC 15 Nature check will reveal that it appears to be worth 1000 GP. However, if the check passes by a value of 25 or more, it will be determined that the gold of the crown is actually mixed with silver, cutting the value down to 500 GP. Alternatively, you could use the crown for another puzzle elsewhere in the dungeon, such as putting it on the head of a statue to open a door.

Many players might attempt to solve this puzzle through alternative means, such as levitating into the well or using spider climb to scale the walls. Use your judgment to determine how this should be addressed - you should reward PCs for thinking outside the box, not punish them for not guessing what you wanted them to do.

Optionally, if you're worried about PCs getting into the well, you can have a water weird at the bottom, lurking in the water. It lays dormant as long as the PCs stay out of the well, but will come to life and attack if they enter it.

Torlandic Topology

So this is probably the single nerdiest thing I've ever done.

The setting for The Saga of the Ortegids, extrapolating from the worldbuilding details we get in the first three Dragon Quest games, is a hollow planet, with Erdland (the world map of Dragon Quest III) on the outside, and Torland (that of Dragon Quest II, which includes that of I) on the inside. Thinking about how both 3 and 2 feature an area where you can obtain a leaf of the Worldtree, I began to ponder how exactly the maps would line up if modeled on a three-dimensional sphere.

So I got a free trial of SketchUp and did exactly that. Look under the cut for more.