Charles Sheeler- Stacks in Celebration

Here we begin with a circle inscribed within a square, with the right-hand margin of the square aligned with the edge of the rightmost smokestack.

To get the aspect ratio in the painting, one begins by drawing diagonals tangent to the circle. Then, construct a small square around their extensions beyond the big square, and draw a small circle around that set of small squares. This construction gives the correct aspect ratio of 1.293.

With the border of the painting thus located, we can construct another big square abutting its right-hand margin. Note that the yellow diagonal of this square defines the edge of the dark blue patch of sky near the tallest smokestack. All the rays in the sky, in fact, seem to result from similar constructions.

To see this, I’ve begun by drawing green verticals through the points where the big circles cut the big diagonals, or each other.

Then, you can simply connect their endpoints to get more lines in the sky.