Rashi: The cedar wood covering the walls was carved with shapes like windings and knobs.

Rashi citing Targum Yonasan: The shapes of round eggs were carved into them.

Radak #1: [The cedar wood was like] woven and bulged like mushrooms.

Radak #2: Mikla'as is Samuch to Peka'im. The form of bulbs was woven. This is like "v'Kala Keruvim" (verse 35) -it was illustrated with Keruvim.

Ralbag: They are like [oval] eggs.

Abarvenel: They carved into the wood the shape of Kela'im (curtains) of the Mishkan, for honor, glory and a remembrance of the Kedushah.

Gra: They were shapes of animals. Peka'im is like Beka (half), for only one side was visible; the other side faced the wall.

Rashi: The form of chains ¹ . Peturei is ropes, as in k'Fiturei b'Fi Veshet (Mo'ed Katan 29a), and Tzitzim are flowers - "va'Yatzetz Tzitz" (Bamidbar 17:23). Radak - the Dagesh in the latter Tzadi is in place of the missing Yud.

Rashi citing Menachem: It is like open flowers. Peturei is like "Peter Rechem" (Shemos 13:12) and "Yaftiru v'Safah" (Tehilim 22:8) (Radak - and "Poter Mayim Reishis Madon" (Mishlei 17:14).