de Bruijn digraph

The vertices of the de Bruijn digraph $B(n,m)$ are all possible words of length $m-1$ chosen from an alphabet of size $n$ .

$B(n,m)$ has $n^{m}$ edges consisting of each possible word of length $m$ from an alphabet of size $n$ . The edge $a_{1}a_{2}\dots a_{n}$ connects the vertex $a_{1}a_{2}\dots a_{n-1}$ to the vertex $a_{2}a_{3}\dots a_{n}$ .

For example, $B(2,4)$ could be drawn as: