Translation of some Chinese characters (to English)

[Rukia-chan]

Hi ^^

I have a bed sheet with Chinese characters on it that I'm curious to know the meaning, it's the same expression repeated twice, here are the pictures:

And each character alone:

Thanks in advance everyone! ^^

[Iriya]

莊周夢蝶

http://en.wikipedia.org/wiki/Zhuangzi#The_butterfly_dream

[Rukia-chan]

Thanks a bunch ^^