article_snippet: Scroll down for video .
article_snippet: __________' last year .
article_snippet: It had a Cards Against Humanity branding at the bottom, referring to the popular card game.
article_snippet: The space is supposed to be filled by a word.
article_snippet: Mr Engler said: It’s mystifying.
article_snippet: Nothing I’ve learned leads to even a hint of an explanation, which might never be forthcoming.