No one knows if this was a real tower. A tower is a tall, slender building, and saying that David built it implies that it was beautiful. The man considered the woman's neck long and slender and so beautiful. AT: "Your neck is long and beautiful like the tower of David" (See: [[rc://en/ta/man/translate/figs-simile]])
Women had necklaces that covered their entire necks with rows of decorations. The man compares these rows of decorations with the rows of stone on the tower. AT: "that has many rows of stone" (See: [[rc://en/ta/man/translate/figs-metaphor]] and [[rc://en/ta/man/translate/figs-activepassive]])
The man compares the decorations of the woman's necklace with shields hanging on the tower. The necklace probably went around her neck many times. (See: [[rc://en/ta/man/translate/figs-metaphor]])