In your opinion, what square on this board is when purple becomes blue?

I would say it depends on the column, but on the far right I would say 30G is purple and 30H is blue according to how it looks on my monitor.

23-I.

What about you?

Between G and H between 20 and 21.

tough one, but maybe G-25

I28

Bingo!

G 29

L23

D27

H30

G29

G 30

E-30 🤔

H20

23i

H26

I don't thibk its one particular sqare...its a line