This is a form of folk art woodcarving says Stuart King, it has been practiced all over Europe from Romania to Russia, from Poland to Scandinavia and was often executed with nothing more than a pocket knife to while away the time.
Chris Pye has been a professional carver for more than 20 years and writes extensively on the subject. His previous books include Lettercarving in Wood, Relief Carving in Wood and Elements of Woodcarving.