anchor.diff:  
   # SimpleITK
   RUN \
  -    mkdir simpleitk && \
  -    cd simpleitk && \
  -    git clone --recursive http://itk.org/SimpleITK.git -b $SIMPLEITK_VERSION && \
  -    mkdir build && \
  -    cd build && \
  -    cmake -DPYTHON_EXECUTABLE=/usr/bin/python3 -DPYTHON_INCLUDE_DIR=/usr/include/python3.5 -DPYTHON_INCLUDE_DIR=/usr/include/x86_64-linux-gnu/python3.5m -DPYTHON_LIBRARY=/usr/lib/x86_64-linux-gnu/libpython3.5m.so.1 -DWRAP_JAVA=OFF -DWRAP_CSHARP=OFF -DWRAP_RUBY=OFF ../SimpleITK/SuperBuild && \  
  -    make -j 2 && \
  -    cd ../..
  -
  -RUN echo "export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:$pwd/simpleitk/build/lib" >> /root/.bashrc
  -
  -# VTK
  -RUN \
  -    mkdir vtk && \
  -    cd vtk && \
  -    git clone https://gitlab.kitware.com/vtk/vtk.git -b $VTK_VERSION && \
  -    mkdir build && \
  -    cd build && \
  -
  -
  -
  -
  -    cd ../..
  -
  -
  -# FSL
  -#RUN \
  -#    apt-get install fsl-complete && \
  -#    source /etc/fsl/5.0/fsl.sh
  -
  -# ENV FSLPARALLEL=condor
  +    if [ ! -e  simpleitk ]; then \
  +        mkdir simpleitk && \
  +        cd simpleitk && \
  +        git clone --recursive http://itk.org/SimpleITK.git -b $SIMPLEITK_VERSION && \
  +        mkdir build && \
  +        cd build && \
  +        cmake -DPYTHON_EXECUTABLE=/usr/bin/python3 -DPYTHON_INCLUDE_DIR=/usr/include/python3.5 -DPYTHON_INCLUDE_DIR=/usr/include/x86_64-linux-gnu/python3.5m -DPYTHON_LIBRARY=/usr/lib/x86_64-linux-gnu/libpython3.5m.so.1 -DWRAP_JAVA=OFF -DWRAP_CSHARP=OFF -DWRAP_RUBY=OFF ../SimpleITK/SuperBuild && \
  +        make -j $N_CPUS && \
  +        cd ../..
  +    fi
  +
  +RUN echo "addlibpath $pwd/simpleitk/build/lib" >> $BASHRC
  +
  +#-------------------------------------------------------------------------------
  +# VTK (http://www.vtk.org)
  +#-------------------------------------------------------------------------------
  +RUN \
  +    if [ ! -e  vtk ]; then \
  +        mkdir vtk && \
  +        cd vtk && \
  +        git clone https://gitlab.kitware.com/vtk/vtk.git -b $VTK_VERSION VTK && \
  +        mkdir build && \
  +        cd build && \
  +        cmake -DPYTHON_EXECUTABLE=/usr/bin/python3 \
  +              -DPYTHON_INCLUDE_DIR=/usr/include/python3.5 \
  +              -DPYTHON_INCLUDE_DIR=/usr/include/x86_64-linux-gnu/python3.5m \
  +              -DPYTHON_LIBRARY=/usr/lib/x86_64-linux-gnu/libpython3.5m.so.1 \
  +              ../VTK && \
  +        make -j $N_CPUS && \
  +        make install && \
  +        cd ../.. \
  +    fi
  +
  +RUN echo "addlibpath $pwd/vtk/build/lib" >> $BASHRC
  +
  +RUN ldconfig
  +
  +# ITK
  +# RUN \
  +#     mkdir itk && \
  +#     cd itk && \
  +#     git clone http://itk.org/ITK.git -b $ITK_VERSION && \
  +#     mkdir build && \
  +#     cd build && \
  +#     cmake -DPYTHON_EXECUTABLE=/usr/bin/python3 \
  +#           -DPYTHON_INCLUDE_DIR=/usr/include/python3.5 \
  +#           -DPYTHON_INCLUDE_DIR=/usr/include/x86_64-linux-gnu/python3.5m \
  +#           -DPYTHON_LIBRARY=/usr/lib/x86_64-linux-gnu/libpython3.5m.so.1 \
  +#           ../ITK && \
  +#     make -j $N_CPUS && \
  +#     make install && \
  +#     cd ../..
   #
  -#
  -# # ITK
  -# RUN \
  -#     git clone http://itk.org/ITK.git -b $ITK_VERSION
  -#
  -#
  -# # PETPVC
  -# RUN \
  -#     mkdir petpvc
  -#
  -#     git clone https://github.com/UCL/PETPVC.git
  -#     cd PETPVC
  -#     mkdir bu
  +# RUN ldconfig
  +
  +#-------------------------------------------------------------------------------
  +# AFNI
  +# https://afni.nimh.nih.gov/pub/dist/doc/htmldoc/background_install/install_instructs/steps_linux_ubuntu.html#install-steps-linux-ubuntu
  +#-------------------------------------------------------------------------------
  +RUN \
  +    apt-get install -y tcsh xfonts-base python-qt4  && \
  +    apt-get install -y libmotif4 libmotif-dev motif-clients && \
  +    apt-get install -y gsl-bin netpbm gnome-tweak-tool libjpeg62 && \
  +    apt-get update && \
  +    sudo ln -s /usr/lib/x86_64-linux-gnu/libgsl.so /usr/lib/libgsl.so.0 && \
  +    dpkg -i http://mirrors.kernel.org/ubuntu/pool/main/libx/libxp/libxp6_1.0.2-2_amd64.deb && \
  +    apt-get install -f
  +
  +RUN \
  +    chsh -s /usr/bin/tcsh  && \
  +    curl -O https://afni.nimh.nih.gov/pub/dist/bin/linux_fedora_21_64/@update.afni.binaries && \
  +    tcsh @update.afni.binaries -package linux_openmp_64 -do_extras && \
  +    chsh -s /bin/bash
  +
  +RUN \
  +    echo "addapath $HOME/abin" >> $BASHRC
  +
  +
  +#-------------------------------------------------------------------------------
  +# ANTS (https://github.com/stnava/ANTs)
  +#-------------------------------------------------------------------------------
  +RUN \
  +    if [ ! -e  ants ]; then \
  +        mkdir ants && \
  +        cd ants && \
  +        git clone https://github.com/stnava/ANTs.git -b $ANTS_VERSION  && \
  +        mkdir build && \
  +        cd build && \
  +        cmake -DUSE_VTK=ON -DUSE_SYSTEM_VTK=ON -DVTK_DIR=$HOME/vtk/build && \
  +        make -j $N_CPUS && \
  +        make install && \
  +        cd ../.. \
  +    fi
  +
  +RUN \
  +    echo "export ANTSPATH=${HOME}/ants/build/bin" >> $BASHRC
  +    echo "addapath $ANTSPATH" >> $BASHRC
  +
  +
  +RUN ldconfig
  +
  +#-------------------------------------------------------------------------------
  +# PETPVC (https://github.com/UCL/PETPVC)
  +#-------------------------------------------------------------------------------
  +RUN \
  +    if [ ! -e  petpvc ]; then \
  +        mkdir petpvc && \
  +        cd petpvc && \
  +        git clone https://github.com/UCL/PETPVC.git -b $PETPVC_VERSION && \
  +        mkdir build && \
  +        cd build && \
  +        cmake -DITK_DIR=$HOME/ants/build/ITKv4-build && \
  +        make -j $N_CPUS && \
  +        cd ../.. \
  +    fi
  +
  +RUN echo "addapath $HOME/petpvc/build/src" >> $BASHRC
  +
  +
  +RUN ldconfig
  +
  +#-------------------------------------------------------------------------------
  +# Camino (http://camino.cs.ucl.ac.uk/)
  +#-------------------------------------------------------------------------------
  +RUN \
  +    if [ ! -e  camino ]; then \
  +        git clone git://git.code.sf.net/p/camino/code camino \
  +    fi \
  +
  +RUN \
  +    echo "export MANPATH=$HOME/camino/man:$MANPATH" >> $BASHRC && \
  +    echo "addapath $HOME/camino/bin" >> $BASHRC
  +
  +#-------------------------------------------------------------------------------
  +# FSL (http://fsl.fmrib.ox.ac.uk)
  +#-------------------------------------------------------------------------------
  +RUN \
  +    apt-get install fsl-complete && \
  +    echo "source /etc/fsl/5.0/fsl.sh" >> $BASHRC && \
  +    echo "export FSLPARALLEL=condor" >> $BASHRC
  +
  +#-------------------------------------------------------------------------------
  +# Python environment with virtualenvwrapper
  +#-------------------------------------------------------------------------------
  +RUN \
  +    pip instal virtualenvwrapper && \
  +    source /usr/local/bin/virtualenvwrapper.sh
  +    mkvirtualenv -p /usr/bin/python3 pytre
  +    pip install -r root/pypes_requirements.txt
  +
  +ENV WORKON_HOME $HOME/pyenvs
  +
  +RUN \
  +    echo "source /usr/local/bin/virtualenvwrapper.sh" >> $BASHRC && \
  +    echo "export WORKON_HOME=$HOME/pyenvs" >> $BASHRC
  +
  +#-------------------------------------------------------------------------------
  +# source .bashrc
  +RUN source $BASHRC
  
positive.code: 
  # Set environment variables.
  ENV HOME /root
  
  # Define working directory.
  WORKDIR /root
  
negative.code: ENV ITK_VERSION v4.10.0
  ENV VTK_VERSION v7.0.0
  ENV SIMPLEITK_VERSION v0.10.0
  ENV ANTS_VERSION v2.1.0
  ENV N_CPUS 2
  
  # Install.
  RUN \
  