In this picture you can see the Three Mother Letters of Sefer Yetzirah:
See the large Hebrew letter Aleph א?
Now look at the yellow diagonal line. It can be seen as the Hebrew letter Vav pronounced Wow. It can also be seen as the numeral One. The Wow of this Aleph balances and united the red Shin ש the blue final Mem ם.
Life is a dynamic process of balancing between extremes - between hot and cold, between activity and rest, between expanding outward and contracting inward. When it's cold, we seek Fire to warm ourselves up. When it's hot, we look for Water to cool ourselves down.
The lower half of this picture shows the root system of a Tree, resting in the cool, wet Earth.
The first Hebrew letter - Aleph - represents the unification of opposites. At the end of the Passover Seder there is the song, ‘Who Knows One?’ The answer, ‘I know One, One is our God who is in the Heavens and the Earth’. This means that God can be found both outside of ourselves (in the Heavens) and inside of ourselves (and the Earth).