She hesitated for a while and then replied uneasily “You see, it gets darker if somebody touches it.”

“Irreversibly?” he asked doubtfully.

“I think so.”

“Let me try” he said without a single gesture.

She frowned.

“Don't you believe me?”

“Sure I do” he said convincingly.

“So you don't like this colour now.”

“But you're crazy, I admire it, really!”

She made up her mind.

“Okay, go on, touch it.”

He did.

“Can you see how it changed?”

He look intensely at her head and said finally: “no, I cannot. I don't think it changed a bit”.

She started crying quietly.

“What's happened? It didn't change the colour, I swear!”

“That's why I'm crying” she half-whispered.

“Because it didn't change?”

“No, because you didn't see it before”

He opened his eyes wide and after a moment said slowly “I don't see at all what you mean.”

“I know that” she said apologetically.