This particular roller sleeve is carved with a dremel tool with a ball-shaped burr bit. It paints parallel wavy lines. Other carved designs will paint other designs.
1 1/4" PVC pipe sections can be used as the basic sleeves for standard paint roller handles. Besides carving, you can also adhere materials to the sleeve to make designs.
Step 1: Carving the Sleeve
Pencil your design and carve away.
Step 2: Other Carved Roller Sleeves
For more information about design rollers see my larger instructable: https://www.instructables.com/id/Design-Rollers-for-painting
Step 3: Sample Painting
Some of the rollers were tiny, and used other techniques than carving for making the surface designs.