Diagrams for Bobbin Lace

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Original math for Polar Grids

The angle of the polar grid is kept constant with the following theory.

angles

When a is small and r large, the small edge of the pie could be considered straight.

With b = 45 degrees, r1 equals the small pie edge.

The approximation above in math: r_1 = \frac{ 2*\pi*r }{ nr \ of \ segments }' align='absmiddle' title='r_1 = \frac{ 2*\pi*r }{ nr \ of \ segments }

For the circle we get: r_2 = \frac{ 2*\pi*(r + r_1) }{ nr \ of \ segments }' align='absmiddle' title='r_2 = \frac{ 2*\pi*(r + r_1) }{ nr \ of \ segments }

From the mathematical rule: tan(b) = \frac{ r_1 }{ curve \ length }' align='absmiddle' title='tan(b) = \frac{ r_1 }{ curve \ length }

we can deduce: r_1 = \frac{ 2 * \pi * r * tan(b) }{ nr \ of \ segments }' align='absmiddle' title='r_1 = \frac{ 2 * \pi * r * tan(b) }{ nr \ of \ segments }