Julian Priest's patch is number 009933, and he has embroidered the words 'Make a Diff'. A Diff is a software patch - the process of comparing 2 files, and creating a patch file to reconcile the difference. He stitched his patch at the Getty Museum in LA, and posted it to Access Space inside a 3D card of the Museum (see photo).
You can read Julian's brilliant posting on how to make a software patch on the Html Patchwork Wiki
Or you can click directly onto his patch 009933