Way mark

Trail blazing, or trailblazing (way marking in United Kingdom and Ireland), is the practice of marking paths in outdoor recreational areas with blazes, markings that follow each other at certain—though not necessarily exactly defined—distances and mark the direction of the trail.

There are three main types of trail blazing: paint, carvings or affixed markers, with paint being the most widely used.

A painted marking of a consistent shape or shapes (often rectangular), dimension and colour or combination of colours is used along the trail route. The system by which blazes are used to signify turns and endpoints in trails (see below) strongly favors the use of paint blazes.

European countries usually use systems of painted bars or shapes in more than one colour. The Central European Hiking Markers System pictured above is the most widely used standard. This system use three bars - usually one color in between two white bars, with different meanings attached to different colours - in a 10 cm x 10 cm square. Red is often used to mark difficult or summit trails.

Arrows of similar design signal a change of direction. Originally created in the Czech Republic, which has the densest hiking trail system in the world, the standard spread to Slovakia, Poland, Croatia, Bosnia, Ukraine, Bulgaria, Georgia, Brazil and other countries, often thanks to European volunteers marking the trails around the world. Austrian and Swiss trails use a similar system of white and coloured stripes, with some differences from the Czech standard.

In the United States and Canada, it is a single colour, often white, red, blue or yellow. Trails in South Africa are often marked by yellow footprints painted on trees and rocks.

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Wikipedia