Look at the coat through a looking glass.

Then blue is seen as situated behind the mirror.

The event which is its situation depends upon the position of the observer.
The sense-awareness of the blue as situated in a certain event which I call the situation, is thus exhibited as the sense-awareness of a relation between the blue, the percipient event of the observer, the situation, and intervening events.

All nature is in fact required, though only certain intervening events require their characters to be of certain definite sorts.

The ingression of blue into the events of nature is thus exhibited as systematically correlated.