Sweep profile twist options "None" meaning

I am learning the Sweep feature in SW2016. There are Profile Orientation options and Profile Twist options for the Sweep feature. For the profile twist, the help documents explains

"None"  (For 2D paths only.) Aligns the profile normal to the path. No correction is applied.     

How is the profile normal to the path? Does anyone know the detail of the options and please help to explain it. Thanks a lot.

SolidworksParts And Features