[Feature]: Sort surface points by theta (increasing from -pi/2) before plotting

[tkphd]

Description

The surface plot for BM4 has zig-zaggy character due to the order in which points are presented in the data.

Suggested Solution:

Convert $(x,y)$ to $\theta$, sort, then plot the transformed $(x',y')$.

Alternatives:

Sort in increasing order of $y$? But that would create horizontal dashes for the circular interface.

Additional Context:

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