Hacking through jungle growth and clearing away rubble, archaeologists made their way to excavate a house buried at the edge of ruins of a large Maya city in the remote Petén lowlands of northeastern Guatemala. It turned out to have been the studio for royal scribes with a taste for art and a devotion to the heavens as the source of calculations for the ancient culture’s elaborate calendars.

Inside, two of the three standing masonry walls were decorated with a faded but still impressive mural, including a painting of a seated king with a scepter and wearing blue feathers. It seemed that, like the Alec Guinness character in the 1958 movie “The Horse’s Mouth,” no Maya artist could abide a wall without a touch of inspired paint. The third wall, on the east side, appeared to have served as the scribes’ blackboard.

On its badly eroded surface, along with black-painted human figures, were scrawled Mayan glyphs and columns of numbers in the form of bars and dots (bars for the number 5 and dots for 1), based on observations of motions of the Sun, the Moon and planets. The glyphs were delicately painted in red or black. From time to time, thin coats of plaster had been applied over texts to provide a clean slate for new calculations. Still other texts were incised into the plaster surface.