This week’s image comes from Chaco Canyon in New Mexico — it’s a scan of an old slide (c. 1980) showing a very typical T-shaped doorway:
While some doorways at Chaco are rectangular, this T-shaped sort of opening is a hallmark of the place. For what it’s worth, the real color of the sandstone masonry is a slightly pinkish tan; most of the reddish tone in the image comes from color shifts in the slide as it ages.
As for the shape — maybe it was for practicality (easier to get through with an armload of stuff), or maybe it was an artistic decision. We’ll likely never know for sure.
Chaco was a major metropolitan area in the 10th , 11th, and early 12th centuries — then it was swiftly depopulated over just a few years around 1150. The expatriate Chacoans wound up resettling further downstream in the riverbank pueblos their descendants still call home today.