Example Snakemake workflow. (a) workflow definition; hypothesized knowledge requirement for line readability is color-coded on the left next to the line numbers. (b) directed acyclic graph (DAG) of jobs, representing the automatically derived execution plan from the example workflow; job node colors reflect rule colors in the workflow definition. (c) content of script plot-hist.py referred from rule plot_histogram. (d) knowledge requirements for readability by statement category.