From Pattern Notes:

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.”

Additional materials:

• 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);
• wire cutter;
• pliers;
• small screwdriver