*B-6 spoiler*
Hint 1: stand on the ladder island with a double-stacked block adjacent to you so that you can push it
Hint 2: you want to push the double-stacked box into a purple path that ends up on the ladder island. Once you do that, follow the loop yourself!
Hint 3:
| > | V |
| double-stacked box | V |
| player on ladder island | < |
push up, then follow loop.