A dream woke me
The only part of the dream I remember is visualizing a tetrahedron.
I was trying to best describe one using only words, no pictures.
Start with a line of a certain length, duplicate it two more times.
Then, connect these lines so that they end up as an equilateral triangle.
Next, make three more lines of the same length originally used.
Take one and join an end of one of these new lines to one of the corners of the equilateral triangle, placing the free end above the center of that equilateral triangle.
Join the other two lines each at one of the other two corners of the equilateral triangle, joining the three loose ends at the center above the center of the equilateral triangle.
This pyramid shape is a tetrahedron.