In an 1893 textbook, criminologist Hans Gross tells how investigators interpreted this ideograph, which had appeared on the wall of a remote Austrian chapel:

The bird, drawn with a single stroke, represents a parrot, alluding to the great loquacity of the owner of the mark, who was famous housebreaker. The second sign is a church, the third a key. Below, we see three round objects on a line; this, according to the calendar of the Styrian peasantry, is the emblem of St. Stephen, i.e., three stones placed on the ground, alluding to the martyrdom of the Saint by stoning. They here indicate the date, viz., St. Stephen’s Day, 26th December. By the side is an infant in swaddling clothes, this indicates the birth of the Saviour, the date being 25th December. The whole thus means: the owner of the parrot sign intends to break into a church on 26th December. He desires accomplices, and will accordingly be in the neighbourhood of the sign (a lonely chapel in a wood) on 25th December to meet whoever turns up.

“The police, knowing the importance of the signs, took a copy to the Magistrate, a priest helped to interpret the liturgical emblems, and on Christmas day four dangerous criminals were captured near the chapel in the wood.”