Debug `add_bsplines_operator(operator='D0N1', geometry='toroidal')` for rect

Operator seems to have very irregular patterns, way to much variability


<img width="890" height="1525" alt="Image" src="https://github.com/user-attachments/assets/02b1254b-b1bb-4931-8554-51f0b5178c17" />

<img width="2947" height="1532" alt="Image" src="https://github.com/user-attachments/assets/d0e6bcae-bbb2-4219-9ca8-725f8a5ddcf2" />