Commentary for Avodah Zarah 102:15

Assi b. Hiyya refers to an idol partitioned off. The word for partitions here is probably a play on the Hebrew “קלעים” which are found in the Temple. To distinguish the holy curtains from the idolatrous partitions, the Talmud uses a different word, one that sounds like קלקל which means spoiled.

Yose b. Hanina says that the distinction between inside and outside the partition does not apply to the Peor idol or the Mercurius. Both of these idols are, according to the rabbis, worshipped in an unusual way. Peor is worshipped by people defecating on it, and Mercurius by people throwing stones at it.
The Talmud clarifies that what this means is that for these two idols there is no distinction between inside and outside the partitions. If the item is either used in the worship of the idol or is decorative it is always prohibited.