One Powerpoint diagram

I need one growth diagram, one I can amend afterwards – so this needs to be in PowerPoint.

To help I’ve already mapped this simplistically in PPT (see enclosed - it's an indication and I played around on how to display the strands (blue and light blue)) – it needs the neatness of a designer hand. There are about 8 different strands that will run across the time period
- each work strand will have 2-3 sub-activities
- each work strand has their own transition points
- some activities will start later


I would assume that there will be 1-2 iterations, so please advise if you can offer at least 2. Deadline for completion (incl. reviews) is 9 October. So please let me know if this is feasible.

Thank you