english: It's the person that's sliding his hands up and down the levers, so the mechanism itself can be very simple and composed of bicycle parts you can get anywhere in the world.
non_english: Čovek je taj koji prebacuje dlanove sa jednog na drugi kraj poluge, tako da sam mehanizam može biti veoma jednostavan. I sastoji se od delova bicikla koji se mogu naći bilo gde u svetu.