I'd like to propose a modified Zebra puzzle. Still has unique solutions. Not on the internet, so not part of the training set. Similar problem description complexity. Just remove the last constraint (Norwegian lives next to the blue house) and asked negated questions: Who cannot be the water drinker? Who cannot own the zebra? Text of problem here: sandiway.arizona.edu/mzebra.pdf (I tested it on free ChatGPT and DeepSeek-R1 https://youtu.be/3gotauWUcew)