Anchor: One motorcyclist covered in mud riding his motorcycle through the mud.
Entailed: A human on a bike.
Contradiction: Nobody is on a bike.
Contradiction: This assumption is not important at all.
Contradiction: At the age of 30, I have delayed my college loans and returned to graduate school. 
Contradiction: He didn't smile, instead, laughed hysterically.
Contradiction: There are two performers having a show before a large crowd.