Step one: hold your hand up with your palm facing out. Step two: tuck your thumb into the palm of your hand. Step three: use the remaining four fingers to trap your thumb.
This simple hand gesture, introduced by the Canadian Women’s Foundation to signal distress and domestic violence, went viral on TikTok last year – and thanks to its universality it could have been the one thing to save the life of a kidnapped teenager.
The 16-year-old girl, who is from North Carolina in the US, was recently reported missing by her parents.