In 1977, we made a movie about how you build retail spatial interaction models which compute the impacts of new shopping centres on their surroundings. It was made for an Open University Course called Modelling by Mathematics (TM281). It was the 5th in a sequence of 10 half hour programmes designed to teach first year technology students about mathematics. The idea was to take real problems and show how math could help – in this case the focus was on ‘power laws’. I have great hopes that this will become a cult movie, indeed that it will go ‘viral’. Apparently I sound the same but look different – I was so much older then, with a full head of hair and a super kipper tie and wide lapels. You can’t see my pants in the studio setting but I assure you they were ‘bell bottoms’. Anyway somethings never change and we are still bashing away at power laws, gravity models and the like in CASA. Enjoy – if only for the old cars, the old men and the dress sense ! Click here for the Vimeo clip.