I am a professional writer. Occasionally, I click send on an email only to glance at it again and release a long, horrible, Skywalker-esque "noooooooooooooooo!'
I've missed an apostrophe.
This is just a segment of the full flowchart. If you have a lot of trouble with rules like this, or teach English to the apostrophatically challenged, they also make a poster.
This flowchart is an interesting variant on the standard form. It blends the usual bubble/arrow layout with more extensive copy. In this case, I'd say their format works well. The flowchart is easy to read, graphically engaging and plenty useful. Kudos Oatmeal.