Ace design, but I must admit I'm unsure to what its meaning is.. If it has one :o

The dictionary says it's the name for the hard shell part of a cocoon of a butteryfly etc... It's also the name of a science fiction book by John Wyndham, and Wikipedia says the title refers to a greater human evolution.

Is it just a pretty design :p.

(Also.... if I normally wear a medium size t-shirt , should I have got a medium sized hoodie?)