Think of tags as like a book index where you find words and which pages they are on, the same principle applies here. Although it's taken a stage further so it might not be the word, but the subject, so for example if you're looking for things to do with fractal gradients for example. A tag may bring back posts with gradient files, as well as posts that discuss gradients, or tutorials about them.
These variations deform the plane by pinching it towards the origin, making a blob-like shape. The math is similar to that of rose curves, but these are standard variations, not blurs.
Gradient Wave Generator runs in the browser, experiment with the settings to play with this fractal based toy
Composite Wave Fractal runs in the browser, experiment with the settings to play with this fractal based toy