# In each of the user directories 00, 01, 02, ... 20, 
# one must extract the archive tasks.tar
# 
  ( cd 01; tar -xvf ../tasks.tar ; chmod -R u+w * )
# ... 
#
# It is already done for directory 01, but not for the other user directories. 
# 
# ------------------- 
# The archive tasks.tar was built with:
# (cd tasks ; tar -cvf ../tasks.tar heat/ hello/ performance/ pi/ pitfalls/)