diff --git a/appendix b/appendix
index a4cbac9..ff8a035 100644
--- a/appendix
+++ b/appendix
@@ -33,14 +33,38 @@ RUN rm -rf ${REPO_DIR}/book ${REPO_DIR}/docs
 # Convert NB_USER to ENV (from ARG) so that it passes to the child dockerfile
 ENV NB_USER=${NB_USER}
 
+## ONBUILD section. These are run in child Dockerfiles. First thing that is run
+
+ONBUILD USER ${NB_USER}
+
 # ${REPO_DIR} is owned by ${NB_USER}
 ONBUILD COPY --chown=${NB_USER}:${NB_USER} . ${REPO_DIR}/childimage
+
 # Copy Desktop files into ${REPO_DIR}/Desktop if they exist. start will copy to Application dir and Desktop
 ONBUILD RUN if [ -d ${REPO_DIR}/childimage/Desktop ]; then \
         mkdir -p ${REPO_DIR}/Desktop && \
         cp -r ${REPO_DIR}/childimage/Desktop/* ${REPO_DIR}/Desktop/; \
     fi
 
+# Add the environment
+ONBUILD RUN echo "Checking for 'conda-lock.yml' or 'environment.yml'..." && \
+        cd "${REPO_DIR}/childimage/" && \
+        [ -d binder ] && cd binder && \
+        [ -d .binder ] && cd .binder && \
+        if test -f "conda-lock.yml"; then 
+          echo "Using conda-lock.yml" && \
+          conda-lock install --name ${CONDA_ENV}; 
+        elif test -f "environment.yml"; then 
+          echo "Using environment.yml" && \
+          mamba env create --name ${CONDA_ENV} -f environment.yml; 
+        fi && \
+        mamba clean -yaf && \
+        find ${CONDA_DIR} -follow -type f -name '*.a' -delete && \
+        find ${CONDA_DIR} -follow -type f -name '*.js.map' -delete && \
+        if ls ${NB_PYTHON_PREFIX}/lib/python*/site-packages/bokeh/server/static > /dev/null 2>&1; then \
+          find ${NB_PYTHON_PREFIX}/lib/python*/site-packages/bokeh/server/static -follow -type f -name '*.js' ! -name '*.min.js' -delete; \
+        fi
+
 # Revert to default user and home as pwd
 USER ${NB_USER}
 WORKDIR ${HOME}