+\hd{Algorithms}
+
+\algo{Factorial}\algalias{calculate a~factorial}
+\algin A~non-negative integer~$n$
+\:If $n\ge 1$: \cmt{Test if something}
+\::Return $n$
+\:Else:
+\::Return $n \cdot \alg{Factorial}(n-1)$
+\algout The factorial of~$n$
+\endalgo
+