It was spotted all over, at irregular intervals, with arabesque figures, about a foot in diameter, and wrought upon the cloth in patterns of the most jetty black. But these figures partook of the true character of the arabesque only when regarded from a single point of view. By a contrivance now common, and indeed traceable to a very remote period of antiquity, they were made changeable in aspect. To one entering the room, they bore the appearance of simple monstrosities; but upon a farther advance, this appearance gradually departed; and step by step, as the visitor moved his station in the chamber, he saw himself surrounded by an endless succession of the ghastly forms which belong to the superstition of the Norman, or arise in the guilty slumbers of the monk. The phantasmagoric effect was vastly heightened by the artificial introduction of a strong continual current of wind behind the draperies – giving a hideous and uneasy animation to the whole. (20)
The narrator creates less of a bedroom than a haunted house or hall of mirrors.
I could not fail to observe a similar increase in the nervous irritation of her temperament, and in her excitability by trivial causes of fear. She spoke again, and now more frequently and pertinaciously, of the sounds – of the slight sounds – and of the unusual motions among the tapestries, to which she had formerly alluded. (22)
Given the strangeness of the room, we and the narrator can't be sure if Rowena is actually seeing anything at all.
The wind was rushing hurriedly behind the tapestries, and I wished to show her (what, let me confess it, I could not all believe) that those almost inarticulate breathings, and those very gentle variations of the figures upon the wall, were but the natural effects of that customary rushing of the wind. But a deadly pallor, overspreading her face, had proved to me that my exertions to reassure her would be fruitless. She appeared to be fainting, and no attendants were within call. I remembered where was deposited a decanter of light wine which had been ordered by her physicians, and hastened across the chamber to procure it. But, as I stepped beneath the light of the censer, two circumstances of a startling nature attracted my attention. I had felt that some palpable although invisible object had passed lightly by my person; and I saw that there lay upon the golden carpet, in the very middle of the rich lustre thrown from the censer, a shadow – a faint, indefinite shadow of angelic aspect – such as might be fancied for the shadow of a shade. But I was wild with the excitement of an immoderate dose of opium, and heeded these things but little, nor spoke of them to Rowena. (23)
Even when the narrator tells us about something, we can't trust him – he admits to being high on opium while telling us all of this.
And the chin, with its dimples, as in health, might it not be hers? – but had she then grown taller since her malady? What inexpressible madness seized me with that thought? One bound, and I had reached her feet! Shrinking from my touch, she let fall from her head, unloosened, the ghastly cerements which had confined it, and there streamed forth, into the rushing atmosphere of the chamber, huge masses of long and disheveled hair; it was blacker than the raven wings of the midnight! And now slowly opened the eyes of the figure which stood before me. "Here then, at least," I shrieked aloud, "can I never – can I never be mistaken – these are the full, and the black, and the wild eyes – of my lost love – of the lady – of the LADY LIGEIA." (29)
Even in the most bizarre of moments, it's a small perception, a tiny observation (the too-tallness of Rowena) that clues the narrator into what's to come. It just goes to show you how committed Poe is to details – another writer might have focused on something more obvious, like, say, a big old scar. Instead, here we really see how vividly the narrator remembers his dead wife.