Enmeshed

Tanis Galik has trademarked the term 'Interlocking crochet'. Right. So most roads lead back to her and her book. But I did find tutorials to show me how to do it, and discovered that it goes by a number of other names, such as double filet crochet, or intermeshed crochet. It consists of two layers of filet crochet. Each layer is separate, so a white stitch always goes into a white stitch, black into black. The two layers are created at the same time, and the way they are linked creates the pattern. That is, whether a stitch is joined in front of the other layer or behind it. This creates a double layer that is reversible:

For the top sample, I used Nichole Cupp's pattern on Ravelry: ZigZagging Reversible Hotpad. Another site showing the same pattern is this tutorial from Niccupp Crochet. The squares pattern I learnt from angelfire's post, here. I struggled a bit to get going, as you can see from my first sample:

But it's not difficult, I quickly got the hang of it.

When I was researching the subject, I came across this interview with Nickerjac, who is a renowned British designer of double filet crochet. She mentions the East Londen Crochet Group. Their gallery here shows designs that are freestyle, which shows that double filet crochet is not necessarily geometric. Interesting.

PS. I think I've solved my photos problem. I downloaded a Windows resizer to make the photos use less data, and I'm using Paint to crop and write on them.