The patchwork piece (top and back) is slipped over the upper side of the card,
when opened, the card looks like this:
... and depending on the arrangement of possible quilting-stitches, which are going through the paper to the back,
it's often also possible to put an extra note inside:
Here are some more, the method allows for a variety of ways to create patchwork or appliqué motifs and patterns:
This is done with my naturally dyed fabrics: