I had a yellow one when I was a lad. It had one big back wheel, one small front wheel, the tyres had a red ring round them, it had three gears on the top bar with a lever to change them and a big long seat you could give your mates a "backy" with. What's to know ? 
Been a few years since i heard that

(giz a backy). Had cow horns on my bike for that
different look
Probably why my back is fooked now thou
