Shedding Light on Jesus’s Manger
The elongated circles represent mangers dug out of the lower end of the living room. The “family living room” has a slight slope in the direction of the animal stall, which aids in sweeping and washing. Dirt and water naturally move downhill into the space for the animals and can be swept out the door. If the family cow is hungry during the night, she can stand up and eat from mangers cut out of the floor of the living room. Mangers for sheep can be of wood and placed on the floor of the lower level.
Source: A Glass Darkly