triangular space in the irregular north wall
EASTERN ATTIC ROOM
"He studied the timber and plaster walls for traces of cryptic designs at every accessible spot where the paper had peeled, and within a week managed to get the eastern attic room where Keziah was held to have practised her spells. It had been vacant from the first--for no one had ever been willing to stay there long--but the Polish landlord had grown wary about renting it."
"Gilman's room was of good size but queerly irregular shape; the north wall slanting perceptibly inward from the outer to the inner end, while the low ceiling slanted gently downward in the same direction. Aside from an obvious rat-hole and the signs of other stopped-up ones, there was no access--nor any appearance of a former avenue of access-- to the space which must have existed between the slanting wall and the straight outer wall on the house's north side, though a view from the exterior showed where a window had been boarded up at a very remote date."
"The touch of brain-fever and the dreams began early in February. For some time, apparently, the curious angles of Gilman's room had been having a strange, almost hypnotic effect on him; and as the bleak winter advanced he had found himself staring more and more intently at the corner where the down-slanting ceiling met the inward-slanting wall."
"...the rats in the ancient partitions were the worst. Sometimes their scratching seemed not only furtive but deliberate. When it came from beyond the slanting north wall it was mixed with a sort of dry rattling; and when it came from the century-closed loft above the slanting ceiling Gilman always braced himself as if expecting some horror which only bided its time before descending to engulf him utterly."
"He would be lying in the dark fighting to keep awake when a faint lambent glow would seem to shimmer around the centuried room, showing in a violet mist the convergence of angled planes which had seized his brain so insidiously. The horror would appear to pop out of the rat-hole in the corner and patter toward him over the sagging, wide-planked floor with evil expectancy in its tiny, bearded human face; but mercifully, this dream always melted away before the object got close enough to nuzzle him. It had hellishly long, sharp, canine teeth; Gilman tried to stop up the rat-hole every day, but each night the real tenants of the partitions would gnaw away the obstruction, whatever it might be. Once he had the landlord nail a tin over it, but the next night the rats gnawed a fresh hole, in making which they pushed or dragged out into the room a curious little fragment of bone."
"He was also troubled by what some of his fellow lodgers said about his sleep-walking. It seemed that he was often absent from his bed and that the creaking of his floor at certain hours of the night was remarked by the man in the room below. This fellow also spoke of hearing the tread of shod feet in the night; but Gilman was sure he must have been mistaken in this, since shoes as well as other apparel were always precisely in place in the morning. One could develop all sorts of aural delusions in this morbid old house--for did not Gilman himself, even in daylight, now feel certain that noises other than rat-scratching came from the black voids beyond the slanting wall and above the slanting ceiling?"
"However, he knew that he had actually become a somnambulist; for twice at night his room had been found vacant, though with all his clothing in place. Of this he had been assured by Frank Elwood, the one fellow-student whose poverty forced him to room in this squalid and unpopular house. Elwood had been studying in the small hours and had come up for help on a differential equation, only to find Gilman absent. It had been rather presumptuous of him to open the unlocked door after knocking had failed to rouse a response, but he had needed the help very badly and thought that his host would not mind a gentle prodding awake. On neither occasion, though, had Gilman been there; and when told of the matter he wondered where he could have been wandering, barefoot and with only his night clothes on. He resolved to investigate the matter if reports of his sleep-walking continued, and thought of sprinkling flour on the floor of the corridor to see where his footsteps might lead. The door was the only conceivable egress, for there was no possible foothold outside the narrow window."
"The old woman always appeared out of thin air near the corner where the downward slant met the inward slant. She seemed to crystallize at a point closer to the ceiling than to the floor, and every night she was a little nearer and more distinct before the dream shifted. Brown Jenkin, too was always a little nearer at the last, and its yellowish-white fangs glistened shockingly in that unearthly violet phosphorescence. Its shrill loathsome tittering struck more and more into Gilman's head, and he could remember in the morning how it had pronounced the words "Azathoth" and 'Nyarlathotep.'"
"...he also found himself listening intently for some sound in the closed loft above, and half imagining that an evil violet light seeped down through an infinitesimal crack in the low, slanting ceiling." -- Dreams in the Witch House