  Given D and H two digraphs, D is H-coloured iff the arcs of D are coloured
with the vertices of H. After defining what do we mean by an H-walk in the
coloured D, we characterise those H, which we call panchromatic patterns, for
which all D and all H-colourings of D admit a kernel by H-walks. This solves a
problem of Arpin and Linek from 2007.
