Alice's mathematical research into other dimensions includes the "Witch of Agnesi" (Versiera di Agnesi), a graphical curve, whose name arises (fortuitously for the film's subject matter) from a mistranslation of 'versiera' (witch, she-devil), which has the same spelling as the word for a rope used to move a sail.
H.P. Lovecraft's Witch House was filmed in Indiana's Historical Hannah House which is reputed to be haunted.