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Seed Streamlines on a Regular Grid with a Prescribed Length
Seed streamlines on a regular grid and integrate them forward of a particular length.
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pts = Tuples[Range[-2.5, 2.5, 0.5], 2];
In[2]:=

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StreamPlot[{Cos[x + y^3], Sin[y + x^3]}, {x, -3, 3}, {y, -3, 3}, 

 StreamPoints -> {pts -> Thick, Automatic, {Forward, Scaled[0.25]}}, 

 Epilog -> {PointSize[0.015], Black, Point[pts]}, StreamScale -> None,

  StreamColorFunction -> "Rainbow", ImageSize -> Large]
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