Improve example project name `p_marie`

p_marie is suboptimal because of several things:

• It suggests that only marie is working on this project
• It can be interpreted as "Pechmarie" (see also: https://de.wikipedia.org/wiki/Frau_Holle)
• The difference between marie and p_marie is easy to miss

What is a better name for an example project? Maybe p_number_crunch? Other suggestions?