Not so sure the clipped corners indicate anything as REA suggests
"One theory is that these six cards originated from a group of six sheets, stacked on top of one another, that were identically miscut in the lower left corner and along the right side to create the fascinating appearance that we see today. Since they did not meet proper specifications, they were discarded".
There were many (including these) in a recent
goldin auction
To note I do have a bid in
