I occasionally work with maps and charts at work and they're not all the same. Some are in degree:minutes:seconds, and the Army has its own system, and occasionally someone put out stuff in arbitrary x,y coordinates. So if you're working on a map in one system and you need to plot the point on a map with a different system, you have to convert coordinate systems. It's easy (now) that there's software for it.
In figure skating though there's multiple coordinate systems. There's the surface of the rink whose coordinates are the lines, dots and circles. Then there's the boards whose coordinates are the gates, the hockey boxes and any ads painted on the boards. There's the skater who has a 3 dimensional coordinate system. Then finally there's the coach who has a system in her head.
Today my coach put me in the center dot of a hockey circle (coordinate system 1) and had me do a half circle edge (coordinate system 2). She wanted me to do a 3 turn at the top of the half circle.
It turns out, I have no clue where I am on the circle once I start, so after several tries she marked each turn and said, "Look where you're turning."
"Your problem," she said, "Is that you turn when your boobs are pointed at the hockey boxes. Delay your turn until your boobs are pointing to the boards." (coordinate system 4!)
Yes ladies, your boobs have a coordinate system all their own!
So I turn when my boobs are pointing to the boards.
I am now turning late.