Maybe... I wonder.

[If the runes would respond to them, it'd be easy to tell, but since they can't read or use the runes... Papyrus paces around the area, checking on a couple of different pools for whether they have runes or not - and whether the water is steaming.]

Hey! You're onto something. The pools with runes... They're all very hot! Which is a little strange, you'd expect that to be the other way around...