... this is my cell ...

Double, double toil and trouble;
Fire burn and cauldron bubble.

Cool it with a baboon's blood.
Then the charm is firm and good.

O, well done! I commend your pains,
And everyone shall share I'th'gains.
And now about the cauldron sing
Like elves and fairies in a ring,
Enchanting all that you put in.

By the pricking of my thumbs,
Something wicked this way comes.

Macbeth, Act 4. sc. 1
William Shakespeare