root:
             creates   file:./
             creates   file:plan.py
             creates   step:./plan.py

file:./
               state = STATIC
          created by   root:
            supplies   file:f1.txt
            supplies   file:f2.txt
            supplies   file:f3.txt
            supplies   file:plan.py
            supplies   file:work.py
            supplies   step:./plan.py
            supplies   step:./work.py
            supplies   step:cat f1.txt f2.txt > f3.txt

file:plan.py
               state = STATIC
          created by   root:
            consumes   file:./
            supplies   step:./plan.py

step:./plan.py
               state = SUCCEEDED
          created by   root:
            consumes   file:./
            consumes   file:plan.py
             creates   file:f1.txt
             creates   file:work.py
             creates   step:./work.py
             creates   step:cat f1.txt f2.txt > f3.txt

file:f1.txt
               state = STATIC
          created by   step:./plan.py
            consumes   file:./
            supplies   step:cat f1.txt f2.txt > f3.txt

file:work.py
               state = STATIC
          created by   step:./plan.py
            consumes   file:./
            supplies   step:./work.py

step:./work.py
               state = SUCCEEDED
          created by   step:./plan.py
            consumes   file:./
            consumes   file:work.py
             creates   file:f2.txt
            supplies   file:f2.txt

file:f2.txt
               state = BUILT
          created by   step:./work.py
            consumes   file:./
            consumes   step:./work.py
            supplies   step:cat f1.txt f2.txt > f3.txt

step:cat f1.txt f2.txt > f3.txt
               state = FAILED
          created by   step:./plan.py
            consumes   file:./
            consumes   file:f1.txt
            consumes   file:f2.txt
             creates   file:f3.txt
            supplies   file:f3.txt

file:f3.txt
               state = AWAITED
          created by   step:cat f1.txt f2.txt > f3.txt
            consumes   file:./
            consumes   step:cat f1.txt f2.txt > f3.txt
