\documentstyle{article}

\font\foo=dijkstra
\font\bar=dijkstra at 20pt

\begin{document}

{\foo This is a difficult dif{}f{}icult exercise}

{\foo boff finicky flush }

{\foo ABCDEFGHIJKLMNOPQRSTUVWXYZ abcdefghijklmnopqrstuvwxyz
      0123456789 `'"!@\#\$\%\^\&*()-=\`\_+|~[]\{\};':,./<>?}

{\bar This is another difficult test}

\end{document}