anchor.diff:    pip install numpy
   
   # Build and install ninja.
  -RUN git clone https://github.com/martine/ninja.git && \
  +ARG NINJA_VERSION=v1.7.2
  +RUN git clone -b $NINJA_VERSION https://github.com/martine/ninja.git && \
     cd ninja && \
  -  git checkout $NINJA_VERSION && \
     ./configure.py --bootstrap && \
     mv ninja /usr/bin/ && \
     cd .. && \
     rm -rf ninja
   
   # Build and install googletest
  -RUN git clone https://github.com/google/googletest.git && \
  +ARG GTEST_VERSION=release-1.8.0
  +RUN git clone -b $GTEST_VERSION https://github.com/google/googletest.git && \
     mkdir googletest-build && \
     cd googletest-build && \
     cmake -DCMAKE_INSTALL_PREFIX:PATH=/opt/googletest ../googletest && \
  
positive.code:   cd .. && \
    rm -rf $QT_DIR
  
  ARG ITK_VERSION=v4.9.0
  # Build and install ITK
  RUN git clone git://itk.org/ITK.git && \
    cd ITK && \
    git checkout $ITK_VERSION && \
    cd .. && \
    mkdir itk-build && \
    cd itk-build && \
    cmake -G Ninja -DCMAKE_BUILD_TYPE:STRING=Release \
  
negative.code: FROM library/ubuntu:16.04
  MAINTAINER Chris Harris <chris.harris@kitware.com>
  
  RUN apt-get update && apt-get -y install \
    git \
  