From A Beautiful Mind to The Theory of Everything and The Man Who Knew Infinity, Hollywood loves a mathematician. So why cant it get beyond the fevered prodigy scribbling equations on windows?

In the Tina Fey sitcom Unbreakable Kimmy Schmidt, wealthy Manhattanite Jacqueline Vorhees wails to her assistant that she cant afford to get divorced. Even though shed get $1m for every year of her marriage.

I spend 100 grand a month. Ill be broke in 10 years, she wails. No, thats wrong, counters Kimmy (Ellie Kemper), who scribbles some sums with a marker on Mrs Vorheess window. So $100,000 times 12 months. Thats $1.2m a year. Divide that into $12m, and yes, youd be broke in 10 years. But if you invest some of it, assuming a 7% rate of return, using the compound interest formula, your money would almost double.

Kimmy turns round triumphantly: Mrs Voorhees, I mathed, and you can get divorced! Mrs Vorhees eyes Kimmy narrowly. Those are not, she complains, erasable markers. What she doesnt mention is that math isnt a verb. Not yet.

The scene is, among other things, Feys satire of the Hollywood cliche of genius squiggling on glass. In A Beautiful Mind (2001), for instance, Russell Crowe, playing troubled maths star John Forbes Nash Jr, writes formulae on his dorm window. This scene is echoed in The Social Network (2010), where Andrew Garfield sets out the equations for Facebooks business model on a Harvard window while Jesse Eisenbergs Mark Zuckerberg looks on. In the opening scene of Good Will Hunting (1997), janitor prodigy Matt Damon writes equations on a bathroom mirror.

Why do so many Hollywood maths whizzes forego paper? Stanford mathematician Keith Devlin explains. Depicting a mathematician scribbling formulas on a sheet of paper might be more accurate, but it certainly doesnt convey the image of a person passionately involved in mathematics, as does seeing someone write those formulas in steam on a mirror or in wax on a window, nor is it as cinematographically dramatic.

Good point. When we watch A Beautiful Mind and look through the window at our Russ, Hollywoods most built mathematician (counterexamples on postcards, please show your workings), we pass beyond incomprehensible equations and convince ourselves were seeing Genius at Work. Even if, as some critics have complained uncharitably, Russs pi glyphs, greater-than and less-than symbols and such dont make sense.

But theres another way maths movies can confound the Boredom Equation, namely by leaving a black hole where the maths should be. The Man Who Knew Infinity, the new film starring Dev Patel and Jeremy Irons about the great Indian mathematician Srinivasa Ramanujan, is intriguing in this respect. Although we see Ramanujan doing maths, mostly the film is interested in other things how he falls in love with his wife, the pain of separation when he travels from Madras to study at Cambridge, the racism he suffers in England and, most stirringly, the narrative arc from lowly clerk to globally recognised mathematician.

Read more: http://www.theguardian.com/film/2016/apr/06/mathematics-movies-the-man-who-knew-infinity