User blog comment:Thailog/Ep. 206 "Bloodlines" discussion/@comment-98.192.94.165-20120602205749/@comment-1839689-20120602210334

Wally's Aunt Iris gives birth to Don Allen. Don is therefore Wally's first cousin. Don grows up, gets married, and his wife gives birth to Bart. That makes Bart Wally's first cousin once removed. Any children Wally may have one day would be Bart's second cousins. Any children Bart would one day have would be Wally's first cousins twice removed.