Anyone who has owned a Citroen will have used impact technology at one time or another.

My favourite application of this was the BX which, if stalled at traffic lights, would not restart. I carried a large hammer to solve this problem - a quick bash on the starter motor always fixed it but this did lead to some funny looks, also one did tend to resemble Basil Fawlty.

As for 2CVs and derivatives......!! Have you ever heard of a car whose gearbox could unwind? Still love 'em though.