MYSTERY: What is this design, plowed in a Shelley field?

(SHELLEY) — On Wednesday afternoon, local resident Jeff Katseanes sent these pictures to NewsTalk 107.9 in a private Facebook message. Katseanes had been driving near the Shelley exit on I-15, saw that a design had been carved into the freshly-fallen snow, and stopped to take a better look. Katseanes had his camera-equipped drone with him, and sent it into the air.

The drone pictures revealed the pizza-themed design, overlayed with the text “M9SD6L”. A cursory Google search yielded no obvious results. Why a pepperoni pizza? What does the 6-character string mean? Was it aliens, or a bored farmer with incredible tractor-driving skills?

At first glance, the image appears to be an ink sketch on paper, but on closer examination, zooming in on a high-res image, it shows clear plow tracks. Here are the four images sent in by Katseanes:

This may be one of the strangest news tips we’ve ever recieved from a listener. Your thoughts and sleuthing efforts are welcome!