Here's an IBM punch card that was used in the 1960s to program computers:
Here's a 1961 postal money order whose design was based on the IBM punch card:
Now, here's the 1963 Hidell money order:
Notice anything missing from the Hidell money order? (Or rather, not missing?)
Hint: Ask Chris Newton.
EDIT: I no longer believe this to be an issue. Post-1962 cards no longer used the cut-corner feature. See post 41 on page 3.