This is a tool for creating and editing splines within your game. I used this initally for a shmup i was working on where I wanted to create an intresting enemy flight pattern.
The black area represents a 128x128 screen.
Just click in the points you want then press CTRL+C to copy to clipboard This will copy all points to the clipboard as a string.
This string can be then used within your game.

This is what I use it for.

You can test out pasting of splines here. Also this cart has code for handling the splines.