In classical days the constellation was often symbolized by two stars over a ship; and having been appointed by Jove as guardians of Rome, they naturally appeared on all early silver coinage of the republic from about 269 B.C., generally figured as two young men on horseback, with oval caps, surmounted by stars, showing the halves of the egg-shell from which they issued at birth."

The lower halves of the egg-shell were possibly transformed into urns (amforas), because eggs are inherently unstable constructions and tend to roll over:

The ship of Argenidas is perhaps protected by the pair of 'dokana' above.

The 'pile of bricks', the heap of building material, is probably, I guess, related to the Chinese name for χ Gemini:

... χ, a 4th magnitude, with α Cancri, was the Chinese Tseih Tsing, Piled-up Fuel ...

A heap of building material can consist of suitable wooden beams.

More from Allen:

"The sign's symbol, `, has generally been considered the Etrusco-Roman numeral, but Seyffert thinks it a copy of the Spartans' emblem of their Twin Gods carried with them in battle.

Brown derives it from the cuneiform

the ideograph of the Akkad month Kas, the Twins, the Assyrian Simānu, corresponding to parts of our May and June when the sun passed through it.

The constellation was certainly prominent on the Euphrates, for five of its stars marked as many of the ecliptic divisions of that astronomy."

I think the original idea was 'raising the roof of the sky' and the Egyptian quartet of 'sky pillars' was designed very much like the cuneiform Kas, cfr at Heka:

Raising the sky to let in the Sun light should once have been connected with spring equinox rather than midsummer, but precession has moved the roof. Also on Easter Island the new construction work was in high summer (in the month Ko Ruti), cfr at Ure Honu:

... In The Eighth Land Barthel has coordinated the months with activities:

*1 He Anakena*	*4 Tagaroa uri*	*7 Tua haro*	*10 Vaitu nui*
Same as the previous month.	Cleaning up of the fields. Fishing is no longer taboo. Festival of thanksgiving (hakakio) and presents of fowl.	Fishing. Because of the strong sun very little planting is done.	Planting of sweet potatoes.
*2 Hora iti*	*5 Ko Ruti*	*8 Tehetu'upú*	*11 Vaitu potu*
Planting of plants growing above the ground (i.e., bananas, sugarcane, and all types of trees). Good time to fish for eel along the shore.	Cleaning of the banana plantations, but only in the morning since the sun becomes too hot later in the day. Problems with drought. Good month for fishing and the construction of houses (because of the long days).	Like the previous month. Some sweet potatoes are planted where there are a lot of stones (pu).	Beginning of the cold season. No more planting. Fishing is taboo, except for some fishing along the beach. Harvesting of paper mulberry trees (mahute). Making of tapa capes (nua).
3 *Hora nui*	*6 Ko Koró*	*9 Tarahao*	*12 He Maro*
Planting of plants growing below the ground (i.e., sweet potatoes, yams, and taro). A fine spring month.	Because of the increasing heat, work ceases in the fields. Time for fishing, recreation, and festivities. The new houses are occupied (reason for the festivities). Like the previous month, a good time for surfing (ngaru) on the beach of Hangaroa O Tai.	Sweet potatoes are planted in the morning; fishing is done in the afternoon.	Because of the cold weather, nothing grows (tupu meme), and there is hardly any work done in the fields. Hens grow an abundance of feathers, which are used for the festivities. The time of the great festivities begins, also for the father-in-law (te ngongoro mo te hungavai). There is much singing (riu).

An amusing little story from Makemson is suitable for concluding this chapter:

"It must be admitted, however, that the task of raising the sky was not always a long and arduous one. In the New Hebrides of Melanesia the sky was formerly so low overhead that a woman who was pounding roots in a mortar happened to strike the sky with her pestle. Greatly annoyed at the interruption she looked up and cried angrily, 'Go on up higher!' Whereat the sky meekly obeyed her.

What actually happened probably was that the woman struck the low house roof with her pestle and cried angrily to her husband, 'If you don't raise that roof higher, I won't cook you another meal!' thus giving a strong impuls to the development of the science of architecture."