Have you ever wondered, Why is one corner of the SIM card cut off!

A square and rectangle have 4 vertices. If it were a rectangle, there would be 4 possibilities of installation.

If the SIM card were square, there would be 8 placement possibilities.

 To achieve "Fool Proofing", the possibilities need to be reduced to 1. Cutting a corner on the SIM card achieves this result.

"Fool proofing" ensures that even inexperienced assemblers can correctly fit two components.

In engineering, this concept known as Poka Yoke, means “Mistake Proofing