here are two of my first attempts to dive into nukes blinkscript. the basic math taken from an excellent tutorial which you can find here. written by Matt Estela and Pedro Andrade.
therefore i could concentrate on understanding blink as language rather than also thinking about the basic ideas.

both are generating images instead of manipulating. the first one is a radial gradient and second ones are just rings.

 

on vimeo

what i really like about those is, that they always filling up the entire image and not cut off, when the center is even out of the bbox. also the rings  can be really scaled down a lot and offering so quite some fine detail if needed.