A fan theory states that there are over 280 TV shows that exist in the same Universe! Learn about it
Due to crossovers and spinoffs, some believe that 280+ TV shows all take place in the same universe, which exists inside the head of an autistic child - it's called the Tommy Whestphall Universe Hypothesis! Artist Nicholas W Skyles has designed a "poster" and a new way to read Tommy's mind. The Tommy Westphall Multiverse, also known as The Hypothesis, a name given to it by someone who wanted to tear down this silly internet meme, was born in the depths of usenet-at alt.tv.homicide, specifically. In particular, Tom Fontana, an Executive Producer on Homicide Life on the Street, who actually liked putting these links in.
To his huge nerd credit, apart from crossing over characters from Elsewhere, Law & Order, before it had a franchise of its own, and Chicago Hope, he also threw in references to companies that tied his little worlds together. For example, the hospital management company that ran St Eligius in Elsewhere was called Ecumena. That was taken over by the Weigert Corporation, which later turned up in Oz to take over the prison hospital. That’s why we didn’t strictly abide by character crossovers alone; plus if we knew the producers meant the reference to be there, we kept stringing shows into the grid.
None of it was ever meant to be taken too seriously, but it was amazing the number of crossovers that have invaded television. Even discounting the tenuous links there are masses of character crossovers in the Multiverse – easily the bulk of the links in the original spreadsheet and now Nick Skyles’ new design.