A symbol like this one was scorched into the staircase timber of an early Georgian house I've just researched in Hampstead.  The symbols, also known as apotropaic marks, most commonly took the form of a 'Daisy Wheel' which was drawn with a compass in a single endless line which was meant to confuse and entrap evil spirits.  The patterns include flower-like designs, pentangles and tangles of lines to flummox spirits that attempted to follow them.  These witches' marks can be found on houses, churches and barns built between about 1550 and 1750 - often near an entry point of the building or the staircase down to the kitchen.

The marks were thought to offer protection and coincide with a period when belief in witchcraft and the supernatural was widespread.  Interiors lit by tallow candles would have been eerily dark once night fell.