In this drawing, two Hebrew letters - a (red vertical) Shin and a (blue horizontal) Mem - are joined by the first Hebrew letter, (a yellow diagonal) Aleph.
According to the Kabbalah, Shin represents Fire, Mem represents Water - two opposite forces (hot and cold, ascending and descending) which come together in Air, represented by the Aleph.
Notice how these letters are also primary geometric shapes. This derives from their simple gematria (single-digeit number value):
* Shin equals three, and a triangle has three sides.
* Mem equals four, and a rectangle has four sides.
* Aleph equals One, and a circle has one side - or an infinite number of sides, as we say,
"God's Name (Shem) is One", and we mean Infinite.
