Pale Fire created by Kinbote, features an entry for a "Botkin, V.," describing this Botkin as an "American scholar of Russian descent"—and referring to a note in the Commentary on line 894 of Shade's poem, in which no such person is directly mentioned but a character suggests that "Kinbote" is "a kind of anagram of Botkin or Botkine". In this interpretation, "Gradus" the murderer is an American named Jack Grey who wanted to kill Judge Goldsworth, whose house "Pale Fire's" commentator—whatever his "true" name is—is renting. Goldsworth had condemned Grey to an asylum from which he escaped shortly before mistakenly killing Shade,
The Missing Shade of Blue he later says, "this instance is so singular, that it is scarcely worth our observing" he cannot be referring to this particular example, but rather to the "type" of exception that it represents. It is also said that when Hume says, "Let all the different shades of that colour, except that single one, be placed before him, descending gradually from the deepest to the lightest; it is plain that he will perceive a blank, where that shade is wanting", he is assuming that colours are composed of a set of distinct independent hues, when in reality they form a continuum.