The Braisa says you can't make a replica of the Beis HaMikdash or its keilim. How in the world can we possibly do that then???
Paul Goldstein, bklyn usa
The prohibition to make a replica of the Beis haMikdash or its Keilim only applies if the replica is the same size as the real keilim. However, if one makes it larger or smaller it is okay (see Rashi, Avodah Zarah 43a, and Shulchan Aruch YD 141:8). Also if one makes a replica of one of the Keilim out of a different material than the original - e.g. he makes a replica of the Menorah out of wood - that is also okay. The basic rule is that it is forbidden to make a replica of the original if the replica would be a Kosher substitute for the original. Thus it is forbidden to make an iron replica of the Menorah because the Menorah could be made from any metal.
This is not a Psak Halachah