Biomedical Engineering Design provides opportunities to flex your engineering muscles…or fingers. Our prosthetic artist client wanted a functional two-joint finger cap capable of articulation for people who have lost a finger. Three others and I brainstormed possibilities and developed a 3D-printed inner mechanism that moved relative to the more proximal residuum. The artist’s silicone cover encloses this device, making it look like nothing happened. A unique part of this device is that there was no attachment to the hand necessary, only an attachment at the tip and room for the flexure lever to touch the lower part of the finger. I learned the intricacies of stereolithographic 3d printing and how to apply proper tolerances to a CAD model with appropriate linkage properties.