J.K Rowling added this to the series.

Dear Fred,

Your mother still knits a jumper with the letter ‘F’ on it every christmas

Missing you.

Love Dad

OH MY GOD. WHY?!

202) The first Christmas after the Battle of Hogwarts, the time came for Molly to knit her sweaters. She broke down in tears when she knitted George a sweater with a 'G' on it, realising it wouldn't need a companion.

Which one of you is the evil twin?