Improv Dwarf Puzzle and other Scattered Thoughts on my last Shattered World session

I ran my Shattered World D&D 5e game last night and here are my scattered thoughts about it in an order of no particularness (if you're playing the Antagonist Relations drinking game, you know why you should take a drink for that sentence).

• Took out my gussied-up Wights for a test spin which was complicated slightly by a series of natural 20s on my attack rolls...
• Back in the 2nd session I gave the PCs a bunch of magic items that 2nd or 3rd level PCs have no business possessing. I told the players then that taking and using the items was a 'devil deal' that they'd pay for in possibly unforeseen ways. 
• One of the ways I'm realizing that the PCs are paying for this devil deal is that I don't pull many punches with encounters, letting them be fairly brutal and being pretty much okay with PCs going unconscious, often multiple PCs at a time, because I know they have potent magic items that they can fall back on.
• Disclaimed a bunch of responsibility as I had been planning to do, which worked out pretty well. 
• The four players in attendance talked over some personal/party goals, they filled in the map and a little to my surprise they decided that they want to go to the Library of Sacred Knowledge and maybe find a fire-breathing dragon on the way to get what they need for a gnome-built dirigible.
• The two goals I got from the group seem to be
• Go to the Library for more information about what really happened/what the situation on the ground is now.
• Find a way to go from the Thalemegos, the gigantic flying ship they're on, to the ground. While the NPC pilot can control speed and direction, he can't control altitude. 
• Despite being down two players, I don't foresee these goals being too incompatible to the missing PCs and I did purposefully leave the Monastery of the Dark Brew off the map so that the player who wrote it in his PC's backstory gets to place it. (for the Antagonist Relations drinking game, take a drink for "Zack uses both foresee and unforeseen in the same post).
• After a slow start and some NPC questioning that might have been long over-due for the game, the player's volunteered their PCs for an exploration of a mountain top Dwarven fort.
• Improving the fort during a short break while players decided on the spells they wanted and made some history (I'm trying to help Thomas bring that phrase into wider usage). I wrote down three things.
• Wights
• Dwarven puzzle
• Barrels
• In the moment, I remembered a promotional trinket I'd gotten from work, a wooden cube puzzle and figured, why not try using that as a prop instead of just trying to describe a trapped door or world puzzle.
• I grabbed the puzzle and took it apart and reassembled it multiple times during the combat with the Wights, until I felt confident that I could easily complete it below is the puzzle I ran with.

Improvized Dwarf Puzzle with Fire Damage and Wood Prop

• A smallish room with doors on two opposite walls.
• In the center of the room is a pedestal with shapes carved into the top.
• The doors exiting the room (from where the PCs enter) have runes carved into them.
• PCs with at least a rudimentary understand of Dwarf can make out runes for "Stone" and "Fire" on them
• Examining the far doors or the pedestal, the PCs can puzzle out that the far doors won't open until the entry doors are shut and something else is done.
• Once the entry doors are shut the PCs see that the shapes on the pedestal are now free of it and no longer carved into the surface. The PCs quickly figure out that they need to assemble the shapes into a cube to open the far doors as the room begins to become uncomfortable warm.
• Have the PCs roll initiative at that point. Each round the PCs can move a single piece of the puzzle or make a hard INT check for a clue. 
• If you're nice you give all the PCs one free bonus INT check.
• If you're nice you let PCs leave the room through the entry doors if they decide things get too hot for them (take a shot if you're playing the Antagonist Relations drinking game for that awful pun).
• The room continues to warm.
1. The first round the PCs take no damage.
2. Beginning with the 2nd round, have each PC make an easy CON check at the start of each of their turns. If they fail, have them take 1 pt of Fire damage.
3. CON save or take 2 pts of fire damage
4. CON save or 3 pts of fire damage
5. CON save or 3 pts of fire damage
6. CON save or 4 pts of fire damage, 1 pt on a successful save
7. CON save or 4 pts of fire damage, 1 pt on a successful save
8. CON save or 5 pts of fire damage, 2 pts on a successful save
• Hopefully the PCs won't need more than 8 rounds, and you can speed things up if you have more players as more players will mean more pieces moved/clues learned in a round.
• Once the puzzle has been completed, the fire damage stops and the far doors open.

So, what did I learn improvising a puzzle prop during a game session?

• It was a nice change of pace, and it definitely felt more visceral than a trapped door for a rogue to examine and make a couple of skill checks on disarming.
• It was a little frustrating for the players, which isn't necessarily a bad thing in small doses, but I'm not going to use them that often.
• Half-assedly mastering a puzzle while doing something else doesn't prepare you to provide useful clues. Several times I had to take a picture with my cell phone of what the players had done, pause, pull the puzzle behind my DM screen, work out the solution again and then use the photo to put it back the way the PCs had left it so that I could provide a clue. 
• The second time I did this, I actually photographed the puzzle step by step as I disassembled it, giving me a series of photos of the proper assembly (when I viewed them in reverse order).
• Next time I find a good puzzle prop, I'll play with it and learn all its secrets outside of the game, though I'll probably take a bunch of pictures to use to help provide clues.
• Stakes! I'm really glad that I had the ambient fire damage that kept escalating, otherwise the puzzle would have felt really tacky and meaningless. The need to solve the puzzle before the PCs went unconscious from heatstroke provided a sense of tension.
• Time! I wish I had a timer so I could have given players 15-30 seconds each turn to make their roll for a clue or to move a piece, between my taking the puzzle behind my screen and a few long player turns as players made full use of the metagame advantage of 6 seconds of game time not being 6 seconds of play time the puzzle dragged on a little longer than I wanted (not to blame the players, that was all my fault).

Once they got the puzzle solved and the door opened, the PCs found the supplies, including barrels(!) that they had come seeking and after taking an inventory decided on a long rest, which will have appropriate consequences when we pick up there next session. Overall, a fairly lowkey session, but it gave me a chance to provide some plot-correction and try out a few new things. And now I know to watch out for props that would make good in game puzzles and to master them when my players aren't watching (Those playing the Antagonist Relations drinking game can take a shot for "Zack starts a sentence with And") .