Warning signs use graphics to communicate, independent of language, a potential danger. Most of the time they're pretty clear: Don't touch this, you'll turn into a skull, this thing can explode. Other times the message is a little more mixed, as with this image Richard F., a friend of mine living in Japan, posted on social media:
Enter a caption (optional) Enter a caption (optional)
If you can read Japanese, you are disqualified from this competition. For the rest of you: What do you think it means? And I'm assuming some of you will come up with caption suggestions.