**Author details**

Thomas G. McKay and Benjamin M. O'Brien

*The Biomimetics Laboratory of the Auckland Bioengineering Institute, The University of Auckland, Level 6, Auckland, New Zealand* 

Iain A. Anderson *The Biomimetics Laboratory of the Auckland Bioengineering Institute, The University of Auckland, Level 6, Auckland, New Zealand Department of Engineering Science, School of Engineering, The University of Auckland, Level 3, Auckland, New Zealand* 
