I gave this a shot with my little standby length of yarn and think I understand what you are trying to do or this is what I understood it to be and probably would have done myself...Hey, I've been wrong before!
Double in Double
Chain 3...the 1st stitch of the 3 chain count is the stitch you are working the dc in dc increase. Count chain stitches and you will have 1 extra.
Chain 5...the 1st stitch of the 5 chain count is the stitch you are working the tr ch tr in to create the above pattern.
If not...please 'splain me too! :rofling: