Symmetric things are often more attractive. Symmetry is also a geometric idea: things may have reflection symmetry or rotational symmetry, and so on. What better way to end this series of Geometry lectures on design than by showing how the design of interactive devices, like mobile phones, relates back to symmetry? Symmetry makes a versatile link between human perception and what interactive devices should be designed to do; it makes a constructive link between what is attractive and natural and what is easy to use.

Harold Thimbleby is professor of computer science at Swansea University where he established the Future Interaction Technology Lab. His passion is designing dependable computer systems to accommodate human error. He has been a Royal Society Wolfson Research Merit award holder and a Royal Society Leverhulme Trust Senior Research Fellow. He has also contributed to the Encyclopedia Brittanica and was Gresham Professor of Geometry between 2001 and 2004.
All of Professor Thimbleby's previous lectures may be accessed here.