diff --git a/pointprocesses/code/hompoissonspikes.m b/pointprocesses/code/hompoissonspikes.m
index ff14a1e..e5caf62 100644
--- a/pointprocesses/code/hompoissonspikes.m
+++ b/pointprocesses/code/hompoissonspikes.m
@@ -17,7 +17,7 @@ function spikes = hompoissonspikes(rate, trials, tmax)
     nintervals = 2*round(tmax/mu);
     for k=1:trials
         % exponential random numbers:
-        intervals = random('Exponential', nintervals, 1);
+        intervals = random('Exponential', mu, nintervals, 1);
         times = cumsum(intervals);
         spikes{k} = times(times<=tmax);
     end
diff --git a/pointprocesses/exercises/pointprocesses01.tex b/pointprocesses/exercises/pointprocesses01.tex
index 6eed3fb..eb78d42 100644
--- a/pointprocesses/exercises/pointprocesses01.tex
+++ b/pointprocesses/exercises/pointprocesses01.tex
@@ -15,7 +15,7 @@
 \else
 \newcommand{\stitle}{}
 \fi
-\header{{\bfseries\large Exercise 8\stitle}}{{\bfseries\large Point processes}}{{\bfseries\large December 3th, 2018}}
+\header{{\bfseries\large Exercise 12\stitle}}{{\bfseries\large Point processes}}{{\bfseries\large January 14th, 2020}}
 \firstpagefooter{Prof. Dr. Jan Benda}{Phone: 29 74573}{Email:
 jan.benda@uni-tuebingen.de}
 \runningfooter{}{\thepage}{}
@@ -137,7 +137,7 @@ jan.benda@uni-tuebingen.de}
     Use this function to plot the first second of the
     spike rasters of the three neurons.
     \begin{solution}
-      \lstinputlisting{../code/spikeraster.m}
+      \lstinputlisting{../code/rasterplot.m}
       \lstinputlisting{../code/plotspikeraster.m}
       \mbox{}\\[-3ex]
       \colorbox{white}{\includegraphics[width=1\textwidth]{spikeraster}}