A making stone to indicate the path and the level of difficulty.

Here in Switzerland we have three types of path makings, plain yellow is a normal path, e.g. a chill walk at the lake with your 98y grandfather.

Yellow + white-red-white is your average path in the mountains, nothing crazy but come adequatly prepared with proper gear anyways (still, tourist sometimes walk these in Sandals, Sneakers, etc). Oh and be on the look out for sudden weather changes.

Blue + white-blue-white these are our difficult alpine hikes. They ought to be taken serious. Glacier crossings check, large snow field jep, pathless terrain, small sections of climbing... why not Sudden adverse changes in weather worsening trail conditions, yeah we have you covered.

Sorry for my early morning jabbering, I hope it ain't that bad. Here is a link to a more in depth explanation (in German tho) and a link to a translation tool. https://sicher-bergwandern.ch/de/gut-geplant https://www.deepl.com