Yep, little holes, which were sometimes built into cards in the early-20th-century heyday, particularly leather cards, in anticipation of people wanting to stitch them together. I recall reading that sometimes a string of rawhide would come with a leather card.
![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
no subject
no subject
no subject
no subject
no subject
And I'd never heard of leather postcards before!