How do you tell where the invisible walls are in fuschia city gym

It takes ALOT of focus, but if you look closely, the invisible wall tiles have small white dots in the corners.Normal walk-over titles don't have thatDirections would be...
1)Go all the way to the right.
2)Go all the way up.
3)Go four spaces to the left.
4)Go as far down as possible from there.
5)As far to the left from there.
6)As much down from there.
7)7 spaces to the left.
8)2 spaces down.
9)3 spaces to the right.
10)2 spaces down.
11)From there, you can go almost any way to go around Koga.