Yesod sheh b'malchut. A primary metaphor for creation is "the garden."
The original Kabbalists derived this from a verse in the second creation story
in the Bible/Torah, Genesis 2:10:
וְנָהָרּ יֹצֵא מֵעֵדֶן לְהַשְׁקֹות אֶת־הַגָּן

"A river issues from Eden to water the garden." 

The garden is a metaphor for Shechinah which correlates with Her role as
the sephirah Malchut--manifesting/birthing/release, creation, into existence.
In every minute of every day. 

So, Omer practice, when the River of the full flow of all of the sephirot in the
progression of the Omer process reaches Yesod, it has readying to fully
materialize in its travels through the earlier sephirot.

This is described by Rabbi El'azar in the Zohar:

"That river gushes and flows, entering the garden, drenching it with supernal
saturation, satisfying it, generating fruit and seed."

The translator, Daniel Matt, footnotes to indicate that souls are the fruit that
Shechinah (Malchut) births. Cool. Another theory about the mystery of life!

Sounds like a good day for love-making. Or, to partner someone in birthing
a vision of goodness. 
 

The photo from our Omer beach walk led to a sand sculpture event, and
I found myself helping a dear friend, Alan Dattner, create his vision--
a Cro-Magnon version of Adam and Eve titled "Eternal Gratitude."