Rashi citing Menachos 86b: The cells had transparent windows open on the outside and sealed on the inside. I.e. they were narrow on the inside and wide on the outside, towards the east ¹ .

Rashi citing Menachem: Also here, Shekufim (refer to 40:16:1:1*) is an expression of Hashkafah (watching over), like "Mi Zos ha'Nishkafah" (Shir ha'Shirim 6:10), "Ki Hishkif mi'Merom Kodsho" (Tehilim 102:20), "El ha'Mashkof" (Shemos 12:22).

Radak: They were sealed. They were not totally sealed ? it is called Chalon only if it is open! Rather, it is like "Chalonei Shekufim Atumim" (Melachim I, 6:4) of Shlomo's Bayis - narrow on the inside and wide on the outside. Here it says only Atumos (narrow on the inside). Here Yonason did not explain; he translates merely 'closed'. In Shlomo's Binyan, he translated 'open on the inside and closed outside.'

Vilna Gaon: The windows had doors to seal the windows.

Malbim: The windows were to bring light "El ha'Ta'im" (to the cells, from the outside). They were sealed with glass.

Rashi: The cells did not have openings to the outside, only they were open to each other. It says in Midos (4:3) that the cells around the Heichal, each had three openings ? one to the cell on its right, one to the cell on its left, and one to the cell on top of it. There were only three cells in the Chatzer in a row, and not on top of them. The middle cell opened to the others. The outer cell by the gate opened to the middle cell and towards the gate, and so did the outer cell on the other side, like it says "Pesach Neged Pesach" (13).

Rashi: Towards the sides, the openings of the cells next to the gate on both sides, their openings faced the air (interior) of the gate. The opening of the north cell to the north of the gate, and the opening of the south cell to the south of the gate. The side openings of the cells are the Eilim. They had windows open to the air. The width of the gate interrupts between the cells. That air is called Penimah la'Sha'ar, for one who enters between the air where the cells jut out on each side, it appears that he enters the gate.

Radak: The Hei after the suffix Mem (for the plural) in Eleihemah is extra; it means Eleihem. The same applies to the Hei after the Nun in "Geviyoseihenah" (1:11). The cells had Eilim. The windows in the walls of the cells, and in the Eilim inside the gate, all around, and also in the Ulamos of the cells and Eilim inside this gate. The same applies to the other gates around, that had Eilim and Ilamim ? they had windows. Ilamos is like Eilim.

Vilna Gaon: The windows opened to the opening of the gate, and la'Elamos (there were five Amos between the first and second cells, and also between the second and third, on each side.

Malbim: They were on the side of the openings, where two Eilim stood. Each cell had two openings opposite each other. The middle cell's openings were to the adjacent cells. The outer cells, one was to the middle cell; the cell facing the gate had an opening towards the gate, and two Eilim stood there. The cell facing outside had an opening facing outside, and two Eilim stood there. Here it teaches that there were windows on the two sides outside - "v'El Eleihemah" (towards the Eilim outside), and "li'Fnimah la'Sha'ar", which faced the gate, and from it one entered the gate.

Rashi: Also the Elamos of each gate had windows.

Vilna Gaon: Refer to 40:16:3:3.

Rashi: There were windows in the wall, to the side of the Azarah, inside.

Radak, Vilna Gaon: The windows that were around ? i.e. they were to the inside, and not to the outside.

Malbim: There were windows on three sides of the cells ? east, south and north. Also the Ulam of the gate had windows; they were open to the Chatzer. These windows by Ayil ha'Pesach were open to the floor next to it, for if they were below, the gate would seal them; it opened until this Amah, like I explained (refer to 40:14:3:3). Also there were windows "Saviv li'Fnimah" ? in the wall of the Chatzer, open to the inside, in every wall of the Chatzer above the cells, to bring light to the Chatzer.

Targum Yonasan: It is a crown. Rashi ? there were crowns on top of the Ayil, like a date tree. In Shlomo's Mikdash, the Targum of "Timoros" (Melachim I, 6:29) is Tzuras Diklin.

Malbim: The 60 Eilim that stood after the cells on the east, they had the form of date trees, for beauty.