Thank you Michael.
Using curve to curve flow is much easier.

Having trouble with flow getting the start of the square helix to begin at the beginning of
the red helix. Tried rotating the circle multiple times to adjust the start position.

Is there a script to find the start of a circle, other than by extruding it ? :-)

Also for several days, when typing these forum messages, my arrow keys do not cause a visible movement
of the vertical bar cursor. The arrow keys do cause the cursor to move, invisibly. The cursor does not show up in its
correct position until another character is typed. ?

(The arrow keys work fine in notepad or onenote)