Category: Manufacturing
Title: Building a House

You want to build a tree house. First you collect your requirements, and send
them to a tree house architect. The architect sends you back a draft, which
you refine multiple times with additional requirements. You then create the
list of needed materials from the plan. These materials fall into several categories,
you order them from several online stores. While the order is processed, you send messages
to several of your friends to build the house. After the house is built, you send invitations
for a tree house party to your friends. In order to buy the snacks for the party, a list
of people that attend the party is created.