Famously, the 'swiss cheese' model [0, critical article] - every layer has holes, so layers of safety are required to reduce the chances of holes lining up (lea

Famously, the 'swiss cheese' model [0, critical article] - every layer has holes, so layers of safety are required to reduce the chances of holes lining up (leading to a failure dropping though - and resulting in an accident). [0] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1298298/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1298298/