In 1843 the Irish mathematician William Rowan Hamilton had been mulling over the problem of how to multiply points in three dimensions. While walking from Dunsink Observatory to the Royal Irish Academy, along by the Royal Canal, the solution came to him in a moment of sudden realization and he scratched the formula for quaternion multiplication into the stone of Broom Bridge. This act of mathematical vandalism was first described to O’Beirn by a school friend, now a mathematician, and the film is a quest to try to understand the equation and map that process.

With thanks to Professor Luke Drury, Dublin Institute for Advanced Studies and Dr Áine McManus and Dr. Peter Kootsookos of Dunsink Observatory. Supported by RIAD, University of Ulster.