TARDIS (Time And Relative Dimension In Space) is a central element in Christopher's favorite TV show (Dr Who, just for those who live in some corner of the world where it is not on TV)
This hat was made with using it as a motif.
The yarns came out of the box where I keep those balls which though good quality (100% wool, alpacca, or such) but only one ball is around...(I keep buying them...errr rescuing them, I can't just leave them perishing in the store among acrylic leftover, can I?) Now I know why... I just had to dig in that box and came up with three balls in the perrfect colors.
Christopher loves the hat, so much, I have a difficult time to get it off his head.
Pattern from here.