The stones show the point on the horizon where the sun rises at the day of the new quarter in spring. The distance between the stones is 9.3 m.
The animation shows the day of the new quarter based on the spring equinox as defined by 1) Height Model Equinox and 2) Refraction Equinox. See definitions in Days-of-the-calendar.
The gradients of the top of the stones are in good alignment with the sun’s path. The sun’s path is exactly right 28 days after the spring equinox, defined as the day before spring equinox according to today’s definition. (“refraction equinox”).
Forest obscures the sun at sun set.