Semi Frequent Undertale Facts on X: "* All release trailers for every version of Undertale have shown the Vent Puzzle from Hotland, it even became a constant gag for every trailer. Submitted
Hotland - Undertale Guide - IGN
Undertale - Guide and Walkthrough - PC - By Scarlettail - GameFAQs
Hotland
Steam Community :: Guide :: Idiot's Guide to Undertale: Chapter 2: Snowy/Snowdin Town