From Pattern Notes:
Important: begin of the pattern is on page 10, the complete pattern is from page 22 and further.
more about Dr. Hinke Osinga and this pattern is found overhere
Note on Gauge: “To preserve the geometry of the manifold one needs to ensure that the horizontal width of the used stitch and its length are in the same ratio as the average distance between mesh points on a level set and the width of the respective band. The crocheting reader will be relieved to hear that these considerations were translated into the crochet instructions below | simply following them slavishly will give a good result.”
0.9m unbendable 4mm or 5mm rod;
1.45m and 2 £ 2.70m bendable 2mm wire;
2 electrical wire connectors (come in bars; available from DIY stores);