anchor.diff:  ENV PATH="/root/.opam/4.03.0/bin:${PATH}"
   
   # Certification stuff
  -RUN apt-get -y -qq update
  -RUN apt-get -y -qq install default-jre
  -RUN wget http://cs.uiowa.edu/~amebsout/qualif.tgz
  -RUN tar xvf qualif.tgz && rm qualif.tgz
  -RUN mv qualif/jkind* .
  -RUN mv qualif/cvc4 .
  -RUN rm -rf qualif
  +# Latest proof-producing cvc4.
  +RUN wget -qq http://cvc4.cs.nyu.edu/cvc4-builds/x86_64-linux-opt-proofs/unstable/cvc4-2016-12-06-x86_64-linux-opt-proofs
  +RUN mv cvc4-2016-12-06-x86_64-linux-opt-proofs bin/cvc4
  +# Retrieve jkind.
  +RUN wget -qq https://github.com/agacek/jkind/releases/download/v3.0.2/jkind-v3.0.2.zip
  +RUN unzip jkind-v3.0.2.zip && rm jkind-v3.0.2.zip
  +RUN mv jkind jkind-dir && mv jkind-dir/jkind jkind-dir/*.jar bin/. && chmod a+x bin/jkind && rm -rf jkind-dir
  +RUN chmod a+x bin/cvc4
  +RUN chmod a+x bin/jkind*
  +# RUN ls -lh bin/cvc4
  +# RUN ls -lh bin/jkind*
  +# RUN exit 2
  +# RUN apt-get -y -qq update
  +# RUN apt-get -y -qq install default-jre
  +# RUN wget http://cs.uiowa.edu/~amebsout/qualif.tgz
  +# RUN tar xvf qualif.tgz && rm qualif.tgz
  +# RUN mv qualif/jkind* .
  +# RUN mv qualif/cvc4 .
  +# RUN rm -rf qualif
   
   # Retrieve and build Kind 2.
   RUN mkdir kind2
  
positive.code: # RUN mv cvc4-2016-11-03-x86_64-linux-opt-proofs cvc4
  
  # Retrieve opam.
  RUN wget https://raw.github.com/ocaml/opam/master/shell/opam_installer.sh -O - | sh -s /usr/local/bin
  RUN echo "y" | opam init
  RUN eval $(opam config env)
  RUN opam update
  
negative.code: RUN apt-get -y -qq install build-essential m4 software-properties-common
  RUN apt-get -y -qq install aspcud unzip
  RUN apt-get -y -qq install ocaml
  RUN apt-get -y -qq install default-jre default-jdk
  
  # Retrieve z3 binary.
  RUN wget -qq https://github.com/Z3Prover/z3/releases/download/z3-4.4.1/z3-4.4.1-x64-ubuntu-14.04.zip
  RUN unzip z3-4.4.1-x64-ubuntu-14.04.zip
  RUN mv z3-4.4.1-x64-ubuntu-14.04/bin/z3 bin/.
  RUN rm -rf z3-4.4.1-x64-ubuntu-14.04.zip z3-4.4.1-x64-ubuntu-14.04/
  
  # Retrieve cvc4 binary
  