diff --git a/docs/programmers/tutorials/workflows/downloads/saplot.py b/docs/programmers/tutorials/workflows/downloads/saplot.py
new file mode 100755
index 00000000..99a2416b
--- /dev/null
+++ b/docs/programmers/tutorials/workflows/downloads/saplot.py
@@ -0,0 +1,40 @@
+#! /usr/bin/env python
+"""
+Make a line plot all price paths produced by `simAsset.R`,
+together with their average value at any given time.
+"""
+import csv
+
+import matplotlib.pyplot as plt
+
+
+plt.style.use('ggplot')
+
+data = open('results.csv')
+rows = csv.reader(data)
+ys = []
+max_y = 0
+for row in rows:
+    y = list(float(item) for item in row)
+    max_y = max(max_y, max(y))
+    ys.append(y)
+
+fig = plt.figure()
+
+# plot "hairy"
+for y in ys:
+    x = range(len(y))
+    plt.plot(x, y, linestyle='solid', color='chartreuse', alpha=(1.0/8))
+
+avgs = []
+ts = zip(*ys)
+N = len(ys)
+for t in ts:
+    avg = sum(t) / N
+    avgs.append(avg)
+plt.plot(x, avgs,  linestyle='solid', linewidth=2, color='darkred', alpha=1.0)
+
+plt.ylim(0, max_y)
+#plt.show()
+
+fig.savefig("saplot.pdf")
diff --git a/docs/programmers/tutorials/workflows/part08.pdf b/docs/programmers/tutorials/workflows/part08.pdf
index 6b29d4e0..21ff987d 100644
Binary files a/docs/programmers/tutorials/workflows/part08.pdf and b/docs/programmers/tutorials/workflows/part08.pdf differ
diff --git a/docs/programmers/tutorials/workflows/part08.tex b/docs/programmers/tutorials/workflows/part08.tex
index e02241f9..74c47e16 100644
--- a/docs/programmers/tutorials/workflows/part08.tex
+++ b/docs/programmers/tutorials/workflows/part08.tex
@@ -18,7 +18,7 @@
   \\[1ex]
   University of Zurich
 }
-\date{November~14--17, 2016}
+\date{January~23--27, 2017}
 
 
 \begin{document}
@@ -88,66 +88,26 @@
 \end{frame}
 
 
-\begin{frame}[fragile]
-  \frametitle{Detour: BLAST, again}
-
-  Another use of the BLAST tool is to search for given ``query''
-  proteins in a data base.  Large curated DBs are available, but one
-  may want to build a custom DB.
-
-  \+
-  Building a DB from a set of FASTA-format files \texttt{p1.faa}
-  \texttt{p2.faa} and \texttt{p3.faa}, and querying it is a 3-step
-  process:
-\begin{sh}
-  cat p1.faa p2.faa p3.faa > db.faa
-  formatdb -i db.faa
-  blastpgp -i q.faa -d db.faa -e ...
-\end{sh}
-
-  \+ The \texttt{formatdb} step produces output files
-  \texttt{db.faa.phr}, \texttt{db.faa.pin}, and \texttt{db.faa.psq}; all
-  these files are \emph{inputs} to the \texttt{blastpgp} program.
-\end{frame}
-
-
-\begin{frame}[fragile]
-  \begin{exercise*}[8.A]
-    Write a \texttt{blastdb.py} script to build a BLAST DB and query it.
-
-    \+
-    The \texttt{blastdb.py} script shall be invoked like this:
-\begin{sh}
-$ python topblast.py query.faa p1.faa [p2.faa ...]
-\end{sh}%$
-    where arguments \texttt{new.faa}, \texttt{p1.faa}, etc. are FASTA-format files.
-
-    \+
-    The script should build a BLAST DB out of the files {p$N$.faa}.
-    Then, it should query this database for occurrences of the
-    proteins in \texttt{query.faa} using \texttt{blastpgp}.
-  \end{exercise*}
-\end{frame}
-
 \begin{frame}
-  \begin{exercise*}[8.B]
-    Find out by running the \texttt{blastdb.py} script of Ex.~8.A:
+  \begin{exercise*}[8.A]
 
-    \+
+    Write a \texttt{priceplot.py} script that performs the following two steps:
     \begin{enumerate}
-    \item What happens if an intermediate step fails and does not
-      produce complete output?
+    \item Run the
+      \href{https://github.com/uzh/gc3pie/blob/master/docs/programmers/tutorials/workflows/downloads/simAsset.R}{\texttt{simAsset.R}}
+      script (from Exercise~6.D) with the parameters given on the command line,
+      and
+    \item Feed the \texttt{results.csv} file it outputs into the
+      \href{https://github.com/uzh/gc3pie/blob/master/docs/programmers/tutorials/workflows/downloads/saplot.py}{\texttt{saplot.py}}
+      script and retrieve the produced \texttt{saplot.pdf} file.
+    \end{enumerate}
 
-      \+
-    \item After the whole sequence turns to TERMINATED state, what is
-      the value of its signal and exitcode?
+    \+
+    Run it like \texttt{simAsset.R}, for example:
+\begin{semiverbatim}
+  \$ python priceplot.py 50 0.04 0.1 0.27 10 40
+\end{semiverbatim}
 
-      \+
-    \item How could you implement a ``cleanup'' feature that removes
-      intermediate results (e.g., the ``\texttt{.phr}'' files) and
-      only keeps the output from \texttt{blastpgp} \textbf{if the
-        whole sequence was successfully executed?}
-    \end{enumerate}
   \end{exercise*}
 \end{frame}
 
@@ -169,36 +129,30 @@
 \begin{frame}[fragile]
   \begin{columns}[t]
     \begin{column}{0.6\textwidth}
-      \begin{lstlisting}
+\begin{lstlisting}[basicstyle=\footnotesize\ttfamily]
 class Pipeline~\HL{(StagedTaskCollection)}~:
   def __init__(self, image):
-    StagedTaskCollection.__init__(self)
+    super(Pipeline).__init__(self)
     self.source = image
 
   def stage0(self):
-    # run 1st step
-    return Application(...)
+    # ...
 
   def stage1(self):
-    if self.tasks[0].execution.exitcode != 0:
-      # set collection signal and exit code,
-      # and state to TERMINATED
-      return (0, 1)
-    else:
-      # run 2nd step
-      return Application(...)
+    # ...
 
   # ...
-  def stage~$N$~(self):
+  def stage~{\bfseries\itshape X}~(self):
     # ...
       \end{lstlisting}
     \end{column}
     \begin{column}{0.4\textwidth}
       \raggedleft
 
-      \+\+
-      Example of~a \texttt{StagedTaskCollection}
-      subclass.
+      \+\+\small
+      Example: \\
+      subclassing a
+      \texttt{StagedTaskCollection}
     \end{column}
   \end{columns}
 \end{frame}
@@ -207,10 +161,10 @@
 \begin{frame}[fragile]
   \begin{columns}[c]
     \begin{column}{0.6\textwidth}
-      \begin{lstlisting}
+      \begin{lstlisting}[basicstyle=\footnotesize\ttfamily]
 class Pipeline(StagedTaskCollection):
   def __init__(self, image):
-    StagedTaskCollection.__init__(self)
+    super(Pipeline).__init__(self)
     self.source = image
 
   def ~\HL{stage0(self)}~:
@@ -220,7 +174,7 @@
     # ...
 
   # ...
-  def ~\HL{stage$\mathbf N$(self)}~:
+  def ~\HL{stage{\bfseries\itshape X}(self)}~:
     # ...
       \end{lstlisting}
     \end{column}
@@ -239,7 +193,7 @@
 \begin{frame}[fragile]
   \begin{columns}[c]
     \begin{column}{0.6\textwidth}
-      \begin{lstlisting}
+      \begin{lstlisting}[basicstyle=\footnotesize\ttfamily]
 class Pipeline(StagedTaskCollection):
   # ...
 
@@ -258,8 +212,8 @@
     \begin{column}{0.4\textwidth}
       \raggedleft
 
-      Each \texttt{stage$N$} method can return a \texttt{Task}
-      instance, that will run as step $N$ in the sequence.
+      Each \texttt{stage{\itshape X}} method can return a \texttt{Task}
+      instance, that will run as the $X$-th step in the sequence.
     \end{column}
   \end{columns}
 \end{frame}
@@ -268,21 +222,20 @@
 \begin{frame}[fragile]
   \begin{columns}[c]
     \begin{column}{0.6\textwidth}
-      \begin{lstlisting}
+      \begin{lstlisting}[basicstyle=\footnotesize\ttfamily]
 class Pipeline(StagedTaskCollection):
   # ...
 
   def stage1(self):
-    ~\HL{if self.tasks[0].execution.exitcode != 0:}~
-      # set collection signal and exit code,
-      # and state to TERMINATED
+    ~\HL{\textbf{if} \textbf{\color{gray} self}.tasks[0].execution.exitcode != 0:}~
+      # bail out
       return (0, 1)
     else:
       # run 2nd step
       return Application(...)
 
   # ...
-  def stage~$N$~(self):
+  def stage~{\bfseries\itshape X}~(self):
     # ...
       \end{lstlisting}
     \end{column}
@@ -301,21 +254,20 @@
 \begin{frame}[fragile]
   \begin{columns}[c]
     \begin{column}{0.6\textwidth}
-      \begin{lstlisting}
+      \begin{lstlisting}[basicstyle=\footnotesize\ttfamily]
 class Pipeline(StagedTaskCollection):
   # ...
 
   def stage1(self):
-    if self.tasks[0].execution.exitcode != 0:
-      # set collection signal and exit code,
-      # and state to TERMINATED
+    if ...:
+      # bail out
       ~\HL{return (0, 1)}~
     else:
       # run 2nd step
       return Application(...)
 
   # ...
-  def stage~$N$~(self):
+  def stage~{\bfseries\itshape X}~(self):
     # ...
       \end{lstlisting}
     \end{column}
@@ -326,22 +278,79 @@
       To abort the sequence, return an integer (termination
       status) or a pair \emph{(signal, exit code)}, instead of a
       \texttt{Task} instance.
+
+      \+
+      This sets the collections' own signal and exit code, and also sets the
+      state as \texttt{TERMINATED}.
     \end{column}
   \end{columns}
 \end{frame}
 
 
+\begin{frame}[fragile]
+  \frametitle{Detour: BLAST, again}
+
+  Another use of the BLAST tool is to search for given ``query''
+  proteins in a data base.  Large curated DBs are available, but one
+  may want to build a custom DB.
+
+  \+
+  Building a DB from a set of FASTA-format files \texttt{p1.faa}
+  \texttt{p2.faa} and \texttt{p3.faa}, and querying it is a 3-step
+  process:
+\begin{sh}
+  cat p1.faa p2.faa p3.faa > db.faa
+  formatdb -i db.faa
+  blastpgp -i q.faa -d db.faa -e ...
+\end{sh}
+
+  \+ The \texttt{formatdb} step produces output files
+  \texttt{db.faa.phr}, \texttt{db.faa.pin}, and \texttt{db.faa.psq}; all
+  these files are \emph{inputs} to the \texttt{blastpgp} program.
+\end{frame}
+
+
+\begin{frame}[fragile]
+  \begin{exercise*}[8.B] \emph{(Difficult)}
+
+    Write a \texttt{blastdb.py} script to build a BLAST DB and query it.
+
+    \+
+    The \texttt{blastdb.py} script shall be invoked like this:
+\begin{sh}
+$ python blastdb.py query.faa p1.faa [p2.faa ...]
+\end{sh}%$
+    where arguments \texttt{new.faa}, \texttt{p1.faa}, etc. are FASTA-format files.
+
+    \+
+    The script should build a BLAST DB out of the files {p$N$.faa}.
+    Then, it should query this database for occurrences of the
+    proteins in \texttt{query.faa} using \texttt{blastpgp}.
+  \end{exercise*}
+\end{frame}
+
+
 \begin{frame}
   \begin{exercise*}[8.C]
-    Rewrite the \texttt{blastdb.py} script from Ex.~8.A to use a
-    \texttt{StagedTaskCollection} and be sure to check that a step is
-    successful before proceeding to the next one.
+    Find out by running the \texttt{blastdb.py} script of Ex.~8.B:
 
     \+
-    Upon successful completion of the pipeline, move the
-    \texttt{blastpgp} output into directory
-    \texttt{/home/ubuntu/results} and then delete all intermediate
-    files and directories.
+    \begin{enumerate}
+    \item What happens if an intermediate step fails and does not
+      produce complete output?
+
+      \+
+    \item After the whole sequence turns to TERMINATED state, what is
+      the value of its signal and exitcode?
+    \end{enumerate}
+  \end{exercise*}
+
+  \+
+  \begin{exercise*}[8.D]
+    Implement (in \texttt{blastdb.py}) a ``cleanup'' feature that removes
+    intermediate results (e.g., the ``\texttt{.phr}'' files) and only keeps the
+    output from \texttt{blastpgp} \emph{if the whole sequence was successfully
+      executed}.
   \end{exercise*}
 \end{frame}
 
diff --git a/docs/programmers/tutorials/workflows/solutions/ex8b.py b/docs/programmers/tutorials/workflows/solutions/ex8b.py
new file mode 100755
index 00000000..905651fb
--- /dev/null
+++ b/docs/programmers/tutorials/workflows/solutions/ex8b.py
@@ -0,0 +1,115 @@
+#! /usr/bin/env python
+
+"""
+Write a `blastdb.py` script to build a BLAST DB and query it.
+
+The `blastdb.py` script shall be invoked like this:
+
+  $ python blastdb.py query.faa p1.faa [p2.faa ...]
+
+where arguments `new.faa`, `p1.faa`, etc. are FASTA-format files.
+
+The script should build a BLAST DB out of the files `pN.faa`.
+Then, it should query this database for occurrences of the
+proteins in `query.faa` using `blastpgp`.
+"""
+
+import os
+from os.path import abspath, basename
+import sys
+
+from gc3libs import Application
+from gc3libs.cmdline import SessionBasedScript
+from gc3libs.quantity import GB, minutes
+
+
+if __name__ == '__main__':
+    from ex8b import BlastDbScript
+    BlastDbScript().run()
+
+
+class BlastDbScript(SessionBasedScript):
+    """
+    Run BLAST on pairs of FAA files.
+    """
+    def __init__(self):
+        super(BlastDbScript, self).__init__(version='1.0')
+    def setup_args(self):
+        self.add_param('new_faa', help="Query FAA")
+        self.add_param('known_faa', nargs='+',
+                       help="Samples to compare to the query")
+    def setup_options(self):
+        self.add_param('--e-value', '-e',
+                       type=float, help="Expectation value")
+        self.add_param('--output-format', '-o', dest='output_fmt',
+                       type=int, help="Output format, int from 0 to 9")
+    def new_tasks(self, extra):
+        return [ BlastDbTasks(self.params.new_faa, self.params.known_faa,
+                              self.params.e_value, self.params.output_fmt) ]
+
+
+class BlastDbTasks(StagedTaskCollection):
+
+    def __init__(self, query, subjects, e_value, output_fmt):
+        self.query = query
+        self.subjects = subjects
+        self.e_value = e_value
+        self.output_fmt = output_fmt
+
+    def stage0(self):
+        return ConcatFastaApp('db.faa', self.subjects)
+
+    def stage1(self):
+        return FormatDbApp(join(self.tasks[0].output_dir, 'db.faa'))
+
+    def stage2(self):
+        return BlastpgpApp(self.query, join(self.tasks[1].output_dir, 'db.faa'), self.e_value, self.output_fmt)
+
+
+class ConcatFastaApp(Application):
+    """Merge FASTA files."""
+    def __init__(self, output_name, input_files):
+        input_names = [basename(infile) for infile in input_files]
+        Application.__init__(
+            self,
+            arguments=(["cat"] + input_names + [">", output_name])
+            inputs=input_files,
+            outputs=[output_name],
+            output_dir=("cat-" + output_name + ".d"),
+            stdout=None,  # redirection operator `>` already does it
+            stderr="errors.txt",
+            requested_memory=1*GB)
+
+
+class FormatDbApp(Application):
+    """Index a (large) FASTA file."""
+    def __init__(self, input_file_path):
+        input_name = basename(input_file_path)
+        output_names = [input_name+suffix for suffix in ('', '.phr', '.pin', '.psq')]
+        Application.__init__(
+            self,
+            arguments=["formatdb", "-i", input_name],
+            inputs=[input_file_path],
+            outputs=[output_names],
+            output_dir=("formatdb-" + input_name + ".d"),
+            stdout="formatdb.log",
+            stderr="formatdb.log",
+            requested_memory=1*GB)
+
+
+class BlastpgpApp(Application):
+    """Run BLAST on two files."""
+    def __init__(self, query_file_path, db_files_path, e_value, output_fmt):
+        q = basename(query_file_path)
+        db = basename(db_files_path)
+        db_files = [db_files_path+suffix for suffix in ('', '.phr', '.pin', '.psq')]
+        Application.__init__(
+            self,
+            arguments=["blastpgp", "-i", q, "-d", db,
+                       "-e", e_value, "-m", output_fmt, "-o", "output.txt"],
+            inputs=([q] + db_files),
+            outputs=["output.txt"],
+            output_dir=("blast-" + inp1 + "-" + inp2 + ".d"),
+            stdout=None,  # BLAST's option `-o` already does this
+            stderr="errors.txt",
+            requested_memory=1*GB)
diff --git a/docs/programmers/tutorials/workflows/solutions/priceplot.py b/docs/programmers/tutorials/workflows/solutions/priceplot.py
new file mode 120000
index 00000000..fcd0662e
--- /dev/null
+++ b/docs/programmers/tutorials/workflows/solutions/priceplot.py
@@ -0,0 +1 @@
+ex8a.py
\ No newline at end of file