- Gabriel’s horn (Wikipedia)
A Gabriel’s horn (also called Torricelli’s trumpet) is a type of geometric figure that has infinite surface area but finite volume. The name refers to the Christian tradition where the archangel Gabriel blows the horn to announce Judgment Day. The properties of this figure were first studied by Italian physicist and mathematician Evangelista Torricelli in the 17th century.
- Maskerade (Wikipedia)
Maskerade is a fantasy novel by British writer Terry Pratchett, the eighteenth book in the Discworld series. The witches Granny Weatherwax and Nanny Ogg visit the Ankh-Morpork Opera House to find Agnes Nitt, a girl from Lancre, and get caught up in a story similar to The Phantom of the Opera.