Idiot:1 Common Sense:0

You know the phrase "idiot-proof"? Have you ever wondered which idiot tested the item/theory and was defeated by it?

Foundation paper piecing is meant to be idiot-proof. And then it met me. 

This is the fourth eighth of an eight piece block - four As and four Bs. 

This is the final A piece. See that pink piece in the middle? Its piece 1, around which all other pieces then fit. 

See that black line about 1/4" away from the right hand edge of the pink piece? Yep, the pink piece is meant to cover that. oops.

I can understand misaligning the pink piece to start with - maybe I lined it up wrong, maybe I trimmed it wrong.

What I can't figure out is how I then pieced 11 more pieces around it and didn't notice the error! 

It's an easy fix, I just need to reprint the foundation and recut some scraps. But still, this is meant to be easy. Focus woman!