Just send it to the Depository!
I made few changes:
1. Insertion point: now stretchable, add a Circle + Text (move, rotate, follows the insertion point)
2. Arrival point: add Text (move, rotate, follows the insertion point)
3. Redisagned UI with 2 pages
Many thanks to Roberto for his advices.
rob, an example of my last object - Sewer shaft (not finished yet):