You walk in the dark, Draymun in the lead. Kheldru follows behind, having recovered his mace. This passage is also five feet wide and covered in worked stone. You idly consider the craftsmanship and know that it is first rate and must have taken years. When you have gone about 40 feet down the passage you notice ahead of you a barely perceivable change in the pattern of the stone blocks on both sides of the wall.
What would you like to do?