The ancient Mesopotamians developed the arch and column, and they were also familiar with the use of domes. They were masters of construction using bricks made of mud, the one thing they had lots of. Brick making was a major Mesopotamian industry, especially in the south, where there wasn't much would and stone was non-existent.
Plaques were sort of a like locks for important buildings in Mesopotamia. The plaque was placed into the doorjamb and then a peg was put into the hole. A rope was wrapped around the peg and was covered with clay and held the door shut. This was very common for important building and the plaques were often decorated with scenes of the home.