Fifteen minutes pass in silence. The eye begins to make out here and there in the darkness bluish slits of night and one star.

And the initial link Potato, Perhaps ( IPH- If- Peut-être), God in Kinbote's commentary:

An execrable pun, deliberately placed in this epigraphic position to stress lack of respect for Death. I remember from my schoolroom days Rabelais’ soi-disant "last words" among other bright bits in some French manual: Je m’en vais chercher le grand peut-être.

Potatoes are often mentioned as ingredients ( accompanying a Sander fish, or a Sudak ) and appear in VNs various descriptions of transparent innards in his various novels ( BS, PF,TT). NB: The vegetable soup has already been sent with illustrations discovered by DBJ.

1.She rang him up around midnight, waking him in the pit of an evanescent, but definitely bad, dream (after all that melted cheese and young potatoes with a bottle of green wine at the hotel's carnotzet). As he scrabbled up the receiver, he groped with the other hand for his reading glasses, without which, by some vagary of concomitant senses, he could not attend to the telephone properly. "You Person?" asked her voice...He already knew, ever since she had recited the contents of the card he had given her on the train, that she pronounced his first name as "You."

2. In fact, we depend on italics to an even greater degree than do, in their arch quaintness, writers of children's books. Human life can be compared to a person dancing in a variety of forms around his own self: thus the vegetables of our first picture book encircled a boy in his dream - green cucumber, blue eggplant, red beet, Potato pere. Potato fils, a girly asparagus, and, oh, many more, their spinning ronde going faster and faster and gradually forming a transparent ring of banded colors around a dead person or planet.

3. A mess of sprouts and mashed potatoes, colorfully mixed with pinkish meat, could be discerned, if properly focused, performing hand-over-fist evolutions in Person's entrails, and one could also make out in that landscape of serpents and caves two or three apple seeds, humble travelers from an earlier meal. His heart was tear-shaped, and undersized for such a big chap.

(2) Bend Sinister:
1. 'First the travel story,' said David....For several nights already Krug had been evolving a serial which dealt with the adventures awaiting David on his way to a distant country (we had stopped at the point where we crouched at the bottom of a sleigh, holding our breaths, very very quiet under sheepskin blankets and empty potato sacks)...'No, not tonight,' said Krug. 'It is much too late and I am busy.'

Stooping a little because of his height, he followed without impatience the passengers that filed out through the bus on to the shining asphalt: two lumpy old ladies in semitransparent raincoats, like potatoes in cellophane; a small boy of seven or eight with a crew cut and a frail, hollowed nape; a many-angled, diffident, elderly cripple, who declined all assistance and came out in parts...

During this ordeal, poor Gradus kept wondering what caused another discomfort which kept troubling him on and off throughout the flight, and which was worse than the babble of the monolinguists. He could not settle what to attribute it to — pork, cabbage, fried potatoes or melon — for upon retasting them one by one in spasmodic retrospect he found little to choose between their different but equally sickening flavors. My own opinion, which I would like the doctor to confirm, is that the French sandwich was engaged in an intestinal internecine war with the "French" fries.

(5) ADA
After that, she had decided, there would be bread-crumbed sander (sudak) with boiled potatoes, hazel-hen (ryabchiki) and that special asparagus (bezukhanka) which does not produce Proust’s After-effect, as cookbooks say.(...)
‘You still beat me at fencing, but I’m the better shot. That’s not real sudak, papa, though it’s tops, I assure you.’(Marina, having failed to obtain the European product in time for the dinner, had chosen the nearest thing, wall-eyed pike, or ‘dory,’ with Tartar sauce and boiled young potatoes.)...‘Ah!’ said Demon, tasting Lord Byron’s Hock. ‘This redeems Our Lady’s Tears.’

Carolyn observed that, unlike me she "can't think why it would be useful to explore something without the intention of coming to any conclusion.... It seems to me that VN likes to leave these little repeated word droppings that don't in themselves add up to anything..." I have the impression that VN references to potatoes and gastro-intestinal troubles (with all the veggies such as asparagus and beets, plus a reference to Proust...) may have been, at first, a description of some kind of discomfort he had experienced as a child and which he explored further ( physical discomfort, psychotic corporeal transparencies or celophane packets.), probably in relation to spirals, death and decay.