I had a really mean, bitter, wheelchair bound teacher in 7th grade. I got looking at the back of her motorized chair one day while she was ripping into us for being alive, and I noticed a little DIN plug on the back that went to her controls. Every day I had to sharpen pencils and pass stuff out, and doing that behind her I reached down and pulled the plug and reversed it...thinking it would just make the chair not work. Well, I was half right, the chair still worked but her controls worked in reverse. So, as soon as she starts pushing controls left, she goes right. Forward is backward. She smacks into a trash can, then her desk, then a kid's desk before she figures out it's all reversed. The wheelchair company comes and the tech guy can't figure it out so they replaced her whole upper control assembly...and probably reversed the polarity up there to correct it. So, next time she turned into a raging bitch I switched it back. Controls all reversed again. I know I'll burn in hell for that, but I still don't care.