Originality is the art of concealing your source.
Franklin P. Jones (1853-1935)
“Apollo (Attic, Ionic, and Homeric Greek: Ἀπόλλων, Apollōn (GENἈπόλλωνος) is one of the most important and complex of the Olympian deities in classical Greek and Roman religion and Greek and Roman mythology. The national divinity of the Greeks, Apollo has been variously recognized as a god of music, truth and prophecy, healing, the sun and light, plague, poetry, and more. Apollo is the son of Zeus and Leto, and has a twin sister, the chaste huntress Artemis. Seen as the most beautiful god and the ideal of the kouros (a beardless, athletic youth), Apollo is considered to be the most Greek of all gods.” [Emphasis mine]. Wikipedia

Also from the article above, on Apollo, regarding Etymology of the name:
“The role of Apollo as god of plague is evident in the invocation of Apollo Smintheus (“mouse Apollo”) by Chryses, the Trojan priest of Apollo, with the purpose of sending a plague against the Greeks (the reasoning behind a god of the plague becoming a god of healing is apotropaic, meaning that the god responsible for bringing the plague must be appeased in order to remove the plague).” Emphasis mine
Again, same article, further exploration of the etymology:
“The stones found in front of the gates of Homeric Troy were the symbols of Apollo. A western Anatolian origin [emphasis mine] may also be bolstered by references to the parallel worship of Artimus (Artemis) and Qλdãns, whose name may be cognate with the Hittite and Doric forms, in surviving Lydian texts. However, recent scholars have cast doubt on the identification of Qλdãns with Apollo.
From an article on the Apollo Space Program:
The program was named after Apollo, the Greek god of light, music, and the sun, by NASA manager Abe Silverstein, who later said that “I was naming the spacecraft like I’d name my baby.” Silverstein chose the name at home one evening, early in 1960, because he felt “Apollo riding his chariot across the Sun was appropriate to the grand scale of the proposed program.” Wikipedia
Joe K is telling us that the circles in the 13 symbol cipher represent The Moon. The Apollo 8 Mission was ongoing at the time of the Lake Herman Road Murders. Knowing that the 8 combined with the circle represents the letter ‘a’ used 3 times in ‘Karadanis’, we can work backward to posit that circle/8 = Moon/8 = A8 = Apollo 8. First mission to the Moon and back- a point of pride for any Greek American, I imagine, even for one so sinister and deranged. The most Greek of the Greek Gods Apollo goes to visit his twin sister, Artemis- The Moon!
Its a confirmation that- yes- we have truly uncovered his identity. It’s classical Greek (the God Apollo), Anatolian Greek even- like Joe. It happened at the time of the first confirmed attack, and the 888 Christ reference of course is calling out Joe’s birthday- well, off by one day- the 26th December. And perhaps he’s saying, with his reference to Apollo: carrying out this ‘plague’ of murders is the only way of appeasing the Mob, by hiding the damage done by Larry Kane in the original slaying of Cheri Jo Bates- with the ultimate goal of having his own Casino- the ‘goose that lays the golden egg’.
There is a deeper meaning to all this. Why was Zodiac obsessed with the God Apollo? Because…
Let us look again at his parents’ situation. Joe K’s father Achilles arrives in NY from Anatolia in 1912. Settles down in Natick, Ma., outside of Boston. Around 1928 he returns to his homeland briefly, then comes back Stateside with a girl 25 years younger than he. He makes her his wife. I believe (if we follow Zodiac’s card and letter cues) this was his own daughter: Calli, or Calliope.

Her last name is never listed as anything but Karadanis. Named for the Greek Goddess ‘Calliope’, one of the muses, and the daughter of Apollo.
If Achilles Karadanis married his daughter, their only child George, Joe, is technically both the son and the brother of Calliope.
This apparently was not such an uncommon occurrence in the isolated hill villages of Anatolia around that time.

Joe might have seen his father Achilles then as an Apollo-like figure. He might also see himself as one too: Apollo become Christ, born near Christmas Day as he was, December 26th, an ‘immaculate conception’, the father the much older Joseph– and back to …his own name Joe, the builder and carpenter.
If Joe is ‘Christ’, and Christ was once Apollo, then he is also Apollo and Artemis is his sister- Artemis the Moon, the mother.

From the ‘Murder is Everywhere’ blogspot- ‘Greece’s Sun and Moon God Twins’:
“As a duet, Apollo and Artemis might be best known for a bloody, Bonnie and Clyde-style episode brought on by an affront to their mother (and them) by the daughter of a king who boasted that her own children were “more beautiful” than Leto’s. Talk about perturbing the wrong folk. Artemis and Apollo promptly punished the prideful mother (Niobe) by slaying all of her children, Artemis by arrows the daughters, and Adonis by arrows the sons. In her anguish the mother turned to stone.”

The Apollo space missions might have dredged up all of these associations- sent them whirling around within Zodiac’s mind.