sentences:  Other practical effects included dummy heads made of condoms with fake blood, which, when hit with an axe, created the image of a skull being crushed.On December 8, 1980, towards the end of the shoot, filming was abandoned for one day when news came over the radio that singer John Lennon had been murdered in New York.This senseless act of violence, carried out by an obsessive fan, took the entire nation by surprise and so as a mark of respect, the filming was put on hold for the day.