they swallowed large brown chunks of it and died in convulsions right in front of him as he sat on his throne- '' fumalo : `` which is made of skulls , do ye ken- '' feemalo : `` he sat there with his elbow on his knee and his fist on his chin , like a man thinking long thoughts , perhaps about squaring the circle or finding the ultimate prime number , all the while watching them writhe and vomit and convulse on the floor of the audience chamber . ''