In the old days, tramps and hobos were believed to operate a sophisticated coding system by leaving marks outside the homes of people they had visited.
The shape of a table meant that the occupier might offer a sit-down meal; three circles, denoting coins, suggested that money might be forthcoming; a cross in a square meant a Christian lived there.
This signing technique has featured in the television series Mad Men, in an episode that contained a flashback to the past of the ad man hero Don Draper.
And a few years ago, there was a craze for “warchalking”, in which a mark chalked on a pavement or wall would signify where you might be able to get wi-fi access.Still, perhaps we should take no chances.
The police believe that a simple cross denotes an “easy target”, so if you happen to spot one on your gatepost, surely the safest thing is to draw a neat circle round it, thus converting it effortlessly into “nothing worth stealing”. …