First of all I have to tell you, that I was wrong with the "down join". Riet was so kind and send me an explanation, which you can read here:
The explanation of our TIAS is getting more complicated now, but there are some of you, who are very good at understanding written descriptions. But one thing is important to say: I always let the color go the way it is presenting.
23) go down on the side of your shuttle motif with DC chain 11, LJ to the lower chain at the point on the bottom of the smal DC ring of the inner flower.
24) continue DC chain 6-6, DC ring 3-3, DC chain 6-6, LJ to p of smal LC ring.
25) work up on the other side: DC chain 6+6 (join to opposite chain), DC ring 3+3 (join to opposite DC 3-3 ring), DC chain 6-6
26) LC ring 12-12
27) continue the DC chain 6+6 (join to opposite chain), DC ring 3+3 (join to the other 2 small rings), chain 6
28) LC ring 12+12 (join to opposite 12-12 LC ring), LC ring 12-12
29) DC chain 6, DC ring 3+3 (join to the other 3 small rings), 6+6 (join to opposite chain), join at the starting point of step 24), LC ring 12+12 (join to opposite 12-12LC ring)
From step 24 to step 29 you have to get a square, which is less high at the top,surrounded on the top by 4 LC rings, and with a small 4 leaf flower in the center.
I wish you to enjoy!