Wow!
This is an ambitious, technically ingenious block. The center looks tricky, but the detailed pattern (with helpful photos) walks you through it one step at a time.

I was intimidated by the complex Celtic symbol (the triquetra, as explained in the pattern intro), but it turned out to be easier than expected, thanks to the clear instructions.

To match the size of my other blocks for this sampler, I needed to omit the last few rounds.

I love the way this turned out! The central motif looks completely mystifying-- especially to non-crocheters-- and the “frame” around the motif is lovely, too. It’s a beautiful design.

(Though a fairly advanced pattern, the only reason it took months to finish was that I set it aside for a long time. Don’t worry; it’s not that tricky. (g))

Though not officially part of the CAL, this block is for my BAMMM Shazaam 2016 afghan.
Shown with Canada Goose block border.