Practising touches of Bob Minor

We've been making steady progress with our daughter Dorothy, and we recently reached the point of practising touches of Bob Minor in which she was unaffected. She has taken to the 3-4 pair in preference to 5-6, so instead of calling three homes with her on the tenors, we tried singles that leave 3-4 unaffected.

The most obvious touch is two singles at wrong, swapping 2 and 5 while 3 makes 2nds.

Another touch is two singles swapping 2 and 6, which are when 4 makes 2nds.

This takes us in the direction of the kind of compositions I like for surprise royal and maximus, with 3-4 remaining in the 3-4 position. Calling singles every time 3 or 4 makes 2nds gives 180:

180 Plain Bob Minor

1  4  23456
-----------
s  s  63425
s  s  53462
s  s  23456
-----------

Every course is 5 leads as usual. In total there are 6 courses available with 3-4 unaffected. The 180 visits all of these courses but doesn't ring the whole of every course. To do that, we need to omit a single somewhere and repeat the whole calling. Just for fun, here it is with 123465 as the half-way row:

360 Plain Bob Minor

1  4  23456
-----------
s  s  63425
s  s  53462
   s  23465
-----------
2 part.

Can this structure be extended to a 720? We need to add 3 courses with 3-4 coursing, in each part. Inserting a block of 3 bobs at the end gets close (these are homes from the point of view of the tenors, but remember that 5-6 are swapped at this point):

600 Plain Bob Minor

1  4  5  23456
--------------
s  s     63425
s  s     53462
   s  3  23465
--------------
2 part.

How to get the missing course in? A single at the second lead, from the plain course, changes the coursing order from 53246 to 56243 (swapping 3 and 6)  and puts 3-4 coursing. So we can insert a pair of singles at 2:

720 Plain Bob Minor

1  2  4  5  23456
-----------------
s     s     63425
s     s     53462
   ss s  3  23465
-----------------
2 part.

and there it is, an extent with a regular structure for 3-4.

To enter this kind of composition (based on numbered calling positions rather than positions of an observation bell) into CompLib, you can use a : to show the end of each course:

1  2  4  5
s     s  : 
s     s  :
   s     :
   s     -:
         -:
         -: