Contours on a landscape

Or Fungus on a tree stump.
The last full day of our Christmas stay with Kettwigefrau, we had a pleasant pre lunch walk-in woods above the Ruhr valley.
It looks as though the growth is continuously managed, there are many tree stumps of varying age, from almost totally rotted away, to just a few months old. 
I’ve no idea what this fungus is called.