The paper ‘Computer simulation of electric field lines’ (Kirkup 1985 Phys. Educ . 20
[http://dx.doi.org/10.1088/0031-9120/20/3/314] 142 [http://dx.doi.org/10.1088/0031-9120/20/3/314] )
appeared in 1985 and contains details of a BBC computer program that does exactly what the title
says.