How to extract the vector from each segment

Hi all,

I m trying to create the chain link parametric model with inputs like chain size and link length.
The linear array is fine but now I want to input the arc and array will be done along crv.

My idea to divide the input crv by chain link spacing and rotate each chain based on the vector created by successive points.
Now i have no idea to extract these successive points or segment to create a particular vector.
Please advise since I m new to GH.

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