Well...it had to happen sooner or later. I hadn't made any Hyperbolic Crochet for quite some time and I was missing the fun of creating these forms. If you haven't tried it yet you must! Have a look at the Institute for Figuring to get some background information, it's fascinating!
This is a multi-coloured Hyperbolic form, that I created by using 8ply yarn with a 4.5mm hook. I went with a bright centre, and had good advice to have a white 'rim' as a contrast. What amazes me is how the colour almost totally disappears when just one row of white is added.
I used a simple DC (Double Crochet = US Single Crochet) stitch, and increased every 2nd stitch. This made the form crenellate quite quickly, each row takes around 50% longer to complete than the previous row.
Here is another form I just finished, it's not as crenellated as the rate of increase I used was 1 in 3 stitches.