1 sn U. Cassuto (Exodus, 353) cites b. Shabbat 98b which says, “What did the tabernacle resemble? A woman walking on the street with her train trailing behind her.” In the expression “the half of the curtain that remains,” the verb agrees in gender with the genitive near it.
2 sn The horns of the altar were indispensable – they were the most sacred part. Blood was put on them; fugitives could cling to them, and the priests would grab the horns of the little altar when making intercessory prayer. They signified power, as horns on an animal did in the wild (and so the word was used for kings as well). The horns may also represent the sacrificial animals killed on the altar.
3 sn The text, as before, uses the prepositional phrase “from it” or “part of it” to say that the horns will be part of the altar – of the same piece as the altar. They were not to be made separately and then attached, but made at the end of the boards used to build the altar (U. Cassuto, Exodus, 363).