Comment by chrismorgan

Somewhat related: the “slippery when wet” road sign used in Australia and New Zealand <https://c.stocksy.com/a/jLM400/z9/1039227.jpg> doesn’t actually depict two tyre treads crossing over in a physically impossible way, but one tyre tread and the edge of the road. I finally realised this for no apparent reason at the age of 29 when cycling through New Zealand. None of my family had realised this, though we’d certainly talked about the signs before: we’d all just just written it off as a weird design.