fofor instance, hololding an ob in o one hand and hitting it wi the other. at first, i'd ask my friends for help, but my teachers told me that was wrong. they insisted i had to be able to do the job myself. i got the point. >> reporter: her own condition gave her insight into the difficulties others might be facing. >> traranslator: usually you'd make an arm the same length as a patient's other one. but sometimes that's not ideal. i thought, why not make the length adjustable. >> reporter: so, she did. the shoulder muscles move the hand part. a mechanism allows it to expand and contract. she is used to her left arm being short. so, for detail work she shortens the prosthetic. she makes it it longer when working with potentially dangerous high temperatures to maintain a safe distance. her own knees have given ideas for a host of functions. they told her what might be useful to otothers. >> translator: of course, the natural way is for both arms to be the same. but i want people to realize that different lengths can be beneficial, too. >> reporter: she continu