Humans might have had architectural inclinations as far back as the Paleolithic era. According to a study in the journal PLOS ONE, researchers have found what might be one of the earliest drawings of a hunter-gatherer camp.

The 13,800-year-old drawing, etched into rock, was discovered near the Molí del Salt rock shelter in northeastern Spain. It depicts a row of seven semicircular shapes, each containing parallel lines. Scientists analyzed the etchings under a microscope and found that they weren’t random incisions—they were the product of the same technique, and had been drawn in a limited time period, LiveScience reports. Further study revealed that the circles’ dimensions were similar to the semicircular huts used by hunter-gatherer societies across the world.

According to the Los Angeles Times, archaeologists also found 12 other slabs covered in drawings. However, researchers say this particular piece is special because most late-Paleolithic art is characterized by figurative animal depictions, or symbols that are believed to have had magical or religious significance. If the stone really does depict a true architectural rendering, then its creator was truly defying our understanding of the era’s artistic conventions.

[h/t LiveScience]