The interesting thing about the set of alphabetic metaphor is that they are reusable, and continually throw a different perspective on things. The different perspective is always Christocentric.
The vav ו when used as a prefix, means 'and'. It's primary metaphor is that God spoke into the void to reveal his holiness or separateness from his creation. Like 'and' the vav distinguished between two things while joining them. It can be said that it 'clarifies' or 'makes distinct'.
From previous usage the yud י represents all that God intended to do, and the final mem ם represents the Son completing the covenant made by the Father.
In יום yom, what God intended to do is made distinct from what the Son completed. It is 'clarified'. We find that each day is a distinct picture of Christ.
Furthermore the days act like table of contents entries pointing to seven other sections of scripture, each of which are also pictures of Christ.
Day 1 - Light is created pointing to the narrative of Adam up through Genesis 5. In this hidden prophecy of Christ, the main theme is that God is made known as being Holy and Love or Light and Dark.
Day 2 - The separation of the waters points to the narrative of Noah who represents Christ as the firmament between the waters above and the waters below.
Day 3 - The dry land points to the narrative of the Fathers where the theme is the inheritance of the land. This portion continues through the narrative of Joseph, who is not one of the Fathers, but is the Son who became the king of kings.
Day 4 - The lights are placed in the firmament as Israel is chosen to be witnesses of God in a world demanding grace. Israel is born out of Egypt by the pillars of light and the cloud. This vignette of Christ continues through the 40 years of Israel's sojourn in the desert.
Day 5 - The life which is abundant points to Israel in the promised land. Though in the historical reality, Israel was not very faithful to God, the prophecy of Christ concerns The Son and his unfaithful bride who were fruitful in the flesh.
Day 6. the flocks and the man and his bride point to the life of Christ when Jesus came as the Shepherd to gather his sheep, and to arrange the marriage of the Lamb.
Day 7 - As the church enters the rest of Christ through the cross, the man and his bride are fruitful and multiplying. The bride is a virgin bride who is fruitful by the fruit of the Spirit, and multiplies through teaching and discipleship.
This layer of the 'fractal' nature of scripture is the fourth layer. The first layer is the unity of the whole Bible, the second is the division between Old and New covenants, the third layer reveals the portions of scripture written by each of the persons of the Godhead.
Genesis is the book of the Father, where the Father says "Look at my Son". The story of Israel is a two part story by the Son who tells in great detail how he loves, woos, and works for his bride, and how she breaks his heart. The New Testament is the two-part story of the Holy Ghost saying "Here comes the bridegroom, and see the marriage of the lamb and their fruitfulness.
This fourth layer (the layer of the days of Genesis 1) divides the history of man into seven section, each being a picture of Christ. Each of these sections divides into vignettes of Christ, and they each divide into smaller pictures down to the yud and vav's (the strokes) making up the individual letters of the alphabet. (BTW jot = iota which is derived from yod. The tittle is a horn. Symbolically the horn is blown at the beginning of a declaration. It distinguished what follows... just like the vav.)