Good, but where do you put the 3rd leg for symmetry? (on a coil next to 4 others)
I’ve been scratching my head over this one for a while too.
I added the 4th one because I really like symmetry.
One could go for 8 triangular coils with 3 legs each instead of 6 square coils with 4 legs each, but the leg count is 24 either way and 6 is fewer coils to build and they each have 90 degree bends which seem easier than 120 degree bends.
But with 4 legs I could all too easily see it twisting, racking and wobbling like a pendulum. So, I doubled the number to give triangle strength and resist buckling initiation loads. It looks like a lot of legs, but there are huge loads that we need to resist.
I like the truss shape that I came up with by following that path. I hope you can find a better solution.
I agree it will have an X shaped region of zero field.
I disagree that zero fields are fine.
DrB never drew it this way to my knowledge. [Although, I vaguely remember that one of the enclosed machines had vertex coils and did not work very well for reasons that Art Carlson was very eloquent and adamant about a few months back.]
When I look at it I see 48 vertexes, each with an odd number (3) of faces.
Of interest there are irreconcilable geometrical issues with the shape.
If the hole is square then the straight to curved transitions cannot be in the same place for the two curves. If they are the same then the hole is very much longer than it is wide. I tried to make that work for hours.
Without the crossovers there are no zero field points:
I believe that DrB referred to square plan form, round cross section coils like these. (Although maybe closer to touching than shown in this plot.)
IMO the funny cusp is an artifact of approximating the ideal infinitely sharp vertex points with the long rounded almost kissing regions of round coils like in WB6.
I further believe that the square plan form reduces it greatly. The sharper the bends can be made, the smaller the funny cusp becomes. It reduces in size to approximately what it would be in a machine with round coils the same radius and spacing as the radius of the curved corners of the square coils.
Here without my notes for your marking pleasure:
P.S. Here it is up close: