What was your favourite thing you have designed?

Question: What was your favourite thing you have designed?
- Keywords:
  design,
  favourite,
  invention
Asked by Scott to Martin, Nicola, Alex, Antonio, Christina on 9 Nov 2015. This question was also asked by niamhomalley11 :), Whitetiger101, 969metd27, 676metd27, 259metd45, Alex_skuja.
- Martin O'Halloran answered on 9 Nov 2015:
  
  The device for diagnosing kidney problems in kids.
  
  The old method was very painful for young children and distressing for parents. With our system, it’s completely painless. This is a major change for everyone involved.
- Nicola Greene answered on 18 Nov 2015:
  
  I designed equipment for emptying septic tanks that was much more affordable for use in Africa. This prevents overflowing septic tanks polluting the environment as they are easier to empty.

Question: What was your favourite thing you have designed?