Lanarkshire police are warning people about a code which they say burglars may be using to target houses.
There are symbols for houses which have alarms, which have been previously burgled, are a good target, have a vulnerable occupant, nothing worth stealing, too risky and wealthy.
Officers say their warning is about crime prevention, after crosses were found on sheds in East Kilbride.
Police there say anyone concerned should ring 101.
Lanarkshire Police are warning householders to be aware of this apparent burglary code, external
Twitter users replying to the Lanarkshire Police are suggesting the symbols are just an urban myth.
Meanwhile, it was reported in January that dog-nappers were using symbols to target homes with pedigree dogs.
Police in County Durham found a series of chalk letters and symbols in January on and near homes in the area.
Similar symbols were found outside houses in Torbay, Devon, in 2013.
Four years earlier Surrey police warned householders, external in Caterham to be aware of circles appearing outside homes, indicating a wealthy target, which they called the "Da Pinchi" code.
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