Colette Patterns shares a tutorial on their blog, The Coletterie, showing how you can add a keyhole and ties to a blouse sleeve. The cut out detail is particularly striking when finished with a contrast bias. They show the tutorial using their Violet blouse pattern, but this will work with any basic sleeve. You could even do this on a finished garment, though it might be a little more fiddly to maneuver the sewing machine needle around the finished sleeve.
Click below for her tutorial:
Tutorial: Add a keyhole and ties to the Violet blouse sleeves, by The Coletterie
[photo from The Coletterie]
Becky PS says
Cuuuuute!