City of Light's Tower
Jump onto the wall to get 8 and 9. Then bounce back in a proper moment. Few Light Seeds can be found inside the tower. Jump onto green Power Plate and collect the balls from the walls and ceiling while you are running. As a result you should collect at least 19 seeds. You will have to bounce off one of side walls to obtain 20. You should be able to see another green ring from the terrace....