If I might offer a couple of suggestions, though nothing of critical importance.
When you are creating a new image, I'd recommend using 'gimp-undo-disable/enable' rather than 'gimp-undo-group-start/end'. There is never any need to undo things with a brand new image; it just takes you back to a completely useless, empty image. The individual steps in an undo group also use up steps/memory allocated to the undo history, potentially causing GIMP to forget undo steps from other images that are open.
Also, 'gimp-context-push' should save all of the settings that you are currently storing in temporary variables (e.g., 'old_context-antialias'). All of the original settings can then be restored with a single call to 'gimp-context-pop'.
Finally, you might consider using 'script-fu-menu-register' instead of specifying the menu path in 'script-fu-register' (a methodology which has been deprecated).
For example, instead of:
(script-fu-register "Pursuit_Curve_samj"
_"<Image>/File/Create/Patterns/Pursuit Curve ..."
:
:
:
use:
(script-fu-register "Pursuit_Curve_samj"
_"Pursuit Curve ..."
:
:
: )
(script-fu-menu-register "Pursuit_Curve_samj"
_"<Image>/File/Create/Patterns"