It's safe to say that you want your doctors to know exactly what they're doing when performing surgery. But how do they train for a vascular operation, which is both extremely tricky and unique to your anatomy? By using 3D printing, that's how. MakerBot's parent company Stratasys is teaming with physicians to create 3D-printed replicas of patients' vascular systems, giving surgeons a way to practice before they poke around your blood vessels. The models use flexible photopolymers (that is, light-sensitive polymers) to recreate the feel of organic tissue, so you don't have to worry that the surgery team is only used to working with hardened plastic.