I tried using Google Sheets for this, as I’ve seen a few other people do for their designs, and I found it really easy to play around with new designs, move around sections, and just try to visualize things. Highly recommend it if you don’t have more specific drafting tools!
For this layout, I wanted to have a few small puzzles, as well as one slightly trickier one, to try and play on expectations.
Starting with a room with a locked door (A) and an unlocked door, you find the key (1) in unlocked room adjacent, and move on to the next set.
For the second set of rooms, there’s a few cells for decoration, but ultimately you have to explore to find a second room. There will be a “False” treasure (F), maybe a chipped stone statue, behind some bars you need to pull a lever (2) to reach. That false treasure could be taken out for a lesser ending, but in the process a hidden wall (B) opens up in the previous room, one that you’re essentially forced to see on your way out.
If the stairs behind the hidden wall are taken down, there’s a hallway with some treasure hidden behind some bars along a corridor, before ultimately coming upon another treasure (F) on a pressure-activated plinth (3). Removing it closes a gate (C) trapping the player in the room. The earlier false treasure can be used to swap the statues and escape with the better treasure.
But finally, the real treasure is behind yet another wall. In that treasure room, a pair of pressure plates/plinths (P) are there that you can place the other treasures on. If both are pressed down, the doorway to the real treasure (T) is revealed!
I am a little worried I may have made this a little complex for this lesson, but I enjoyed coming up with ideas as I was going along.