Quo vadis?

I've been collecting photographs of these white arrows for several weeks and decided to make a photo collage of them today. They seem to be everywhere in the Chilterns, usually painted on the trunks of beech but sometimes on other trees or even fence posts.  I understand that they are provided by the Chiltern Society. Some of the waymarks have numbers (referring to the footpath designation on the definitive footpath map) and/or letters which may reference the parish name or long distance footpaths such as the Shakespeare Way (SW), Chiltern Way (CW) or Shakespeare Way (SW).