Create 3-point tangent arcs connecting two curves.

Input parameters:

1. Ca → First curve for tangent arcs.
2. Cb → Second curve for tangent arcs.
3. Pt → Point on arc interior.
4. Ma → Tangency constraint along the first curve.
   • 0 → Any
   • 1 → Along
   • 2 → Against
   • 3 → Clear
   • 4 → Circle
   • 5 → Shortest
   • 6 → Longest
5. Mb → Tangency constraint along the second curve.
   • 0 → Any
   • 1 → Along
   • 2 → Against
   • 3 → Clear
   • 4 → Circle
   • 5 → Shortest
   • 6 → Longest

Output parameters:

1. Ar → Arcs connecting the first and the second curve.
2. La → Loci at arc start points on the first curve.
3. Lb → Loci at arc end points on the second curve.
4. Xd → Cumulative tangent angle error.