The English phrase “a few sandwiches short of a picnic” has some colourful equivalents around the world, says writer Adam Sharp on Twitter. In Sweden, they say “the wheel is spinning, but the hamster is dead”. The French describe a dimwit as “not the most oxygenated trout in the river”, while in Germany, the very thick are “as bright as a tunnel”. Then there’s the Arabic idiom, “your brain is like two walnuts in a sack”; the Korean, “is your head a decoration?”; and the Hungarian, “mentally, you are a sock”.