“What do you think, Maluṅkyaputta, do you have any desire, lust, or affection for those forms cognizable by the eye that you have not seen and never saw before, that you do not see and would not think might be seen?”
“No, venerable sir.”
“Do you have any desire, lust, or affection for those sounds cognizable by the ear … for those odours cognizable by the nose … for those tastes cognizable by the tongue … for those tactile objects cognizable by the body … for those mental phenomena cognizable by the mind that you have not cognized and never cognized before, that you do not cognize and would not think might be cognized?”
“No, venerable sir.”
“Here, Maluṅkyaputta, regarding things seen, heard, sensed, and cognized by you: in the seen there will be merely the seen; in the heard there will be merely the heard; in the sensed there will be merely the sensed; in the cognized there will be merely the cognized.
It is about not grasping at signs.
If you don't see, hear, smell, taste, touch, think about the desired object, the answer is an obvious no.
What makes you notice/recognize or "see" are the signs(nimittas).
And what, venerable sir, is the signless liberation of mind? Here, with nonattention to all signs, a bhikkhu enters and dwells in the signless concentration of mind. This is called the signless liberation of mind.
SN 41.7
“And what, bhikkhus, is the path leading to the unconditioned?
Signless concentration….
SN 43.12
The one whose defilements are dried up,
Who’s not attached to food,
Whose resort is the liberation
That is signless and empty:
Their track is hard to trace,
Like that of birds in the sky.
Thag 1.92
"It would be a good thing, monks, if the organ of sight were
seared with a red-hot iron pin, on fire, all ablaze, a glowing mass
of flames. Then there would be no seizing of the general appear-
ance (nimitta) or details of visible shapes discernible by the eye.
Monks, consciousness, persisting, might persist in being tied by
the satisfaction in the general appearance or details."
The second door of liberation is signlessness. A sign marks the appearance of something, its form. We recognize things based on their sign, but we are often fooled by the outer form of things. The Buddha said, “Where there is a sign, there is deception.”
For example, when we look up at the sky, we see a particular cloud. But if we look long enough, it seems the cloud we are looking at disappears. The cloud has become rain, mist, or snow, and we don’t recognize it anymore.
If you’ve grown attached to that cloud, you may think, “Oh, my beloved cloud, where are you now? I miss you. You’ve passed from being into nonbeing. I can’t see you anymore.” Maybe you don’t feel this way about a cloud, but this is certainly how you feel when you lose someone who is close to you. Just yesterday your friend was still alive. Now it seems that she has passed from being into nonbeing.
https://www.lionsroar.com/the-doors-of- ... -may-2014/
And what is right speech? Abstaining from lying, from divisive speech, from abusive speech, & from idle chatter: This is called right speech.