I just finished a major production run of simulators for training physicians on how to examine the eye. I needed to deliver 10 units, so I started with 13 mannequins — each with highresolution LCD screens for the backs of the eyes (retinae), an Arduino, and a custom interface board. In addition, I printed holders and mounting brackets for the LCD and each of the two boards. Add to that about 30 wire-wrap connections for power, an LED indicator, and interconnecting the major boards, and you have a recipe for guaranteed failure. The only question was the success rate.