A Is To B As B Is To C (sometimes abreviated to a:b::b:c) is track number 17 on the Geogaddi album. The track title is an example of a golden ratio which is a concept of elementary geometry in design, both human and nature.
Forwards: "One two three four five, six seven eight nine ten. Now in Spanish, then in French, say that twice again." (sample source unknown)
Backwards: "We love you all!" (also forwards)
"I'll be gone about a week. Oh, by the way, I brought..." (forwards and reversed; from the film Season of the Witch)
The Season of the Witch lyrics come from a dream sequence at the start of the film (MP3 sample , where, among other things, the lead female character dreams that her husband is leaving her in a kennel for the week while he goes away. A dog barks in the cage next to hers. You can't hear the "brought her pillow" in the BoC sample - I added it to complete the quote. Note that this is NOT the film of that name in the "Halloween" series; it is a different film, with an alternative title of "Jack's Wife", which I think better conveys the fact that it is essentially a psychological drama and not a horror film - [DC]). (audio sample provided by YELLOW)
"If you go down to the woods today, you'd better not go alone!" (reversed; from the song Teddy Bear's Picnic)
As for "the teddy bear's picnic", thanks to [Krelian] for an interesting observation: the song is from The Singing Detective, a series with a theme of childhood trauma.
It's a melody similar to Napolean XIV's "They're coming to take me away!"
"I don't know, it makes it me nervous. I still, um, I still dream about it. I don't know, I just wish it had never happened. I've admitted the whole thing... the whole... the whole thing goes over and over."
Mike Jedlicka spotted the source: it is apparently an "A & E" Investigative Report, called "Behind Bars: Supermax", in which an interview is held with Tommy Silverstein; the words above are apparently from this interview. Also, what Tommy Silverstein was talking about is when he killed a police officer while in jail.
"So, those prophecies you've been describing" ... "And now to business [matters?]..." (reversed; sample source unknown)
Towards the end of the track, a voice repeats something like "It must be a [message] ... look up there!" [DC]
A Is To B As B Is To C often written a:b::b:c. [DC] notes that this is just a mathematical statement that the ratio of a to b is the same as the ratio of b to c: a/b = b/c. If you take a rectangle whose dimensions are in the so-called golden ratio, e.g. a × b, where a = 1.618... and b = 1, then remove a 1x1 square from it, the remaining rectangle has dimensions b × c, where b = 1 and c = 0.618..., and you will indeed find that "a is to b as b is to c": 1.618/1.000 = 1.000/0.618. The above are rough figures. To be precise, the golden ratio φ is 1.618033989... — in fact, it is (1+√5)/2 — and if you use these exact numbers, then the relationship is perfect: φ/1 = 1/(1-φ), exactly. See interview quotes at head of Geogaddi comments on the use of the golden ratio in art and music. The golden ratio is also the limit of the ratio of consecutive Fibonacci numbers (a series where each number is the sum of the two previous numbers: 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144,...). That is, the sequence of fractions 2/1, 3/2, 5/3, 8/5, 13/8, 21/13, ... tends towards the golden ratio φ. These numbers all crop up in many places in nature. A simple example is the number of spirals seen in the composite flower of a sunflower plant; the number of spirals in one direction will be one fibonacci number, the number in the opposite direction, a different fibonacci number. So also in the cones of conifers, phyllotaxis (arrangement of leaves on stems), and related spirals occur in shells and elsewhere. Dr Math explains.
A correspondent has said that he thinks the Steve Miller song "Fly Like an Eagle" is used in this track, that the same sounds occur in the first part of the song. To add to that: in what it probably just one of those odd coincidences, that the album of the same name (from which the song is taken) ends with a track called "The Window".