Making a seven-branched menorah is prohibited by
the Talmud (Menachot 28a, Avodah Zarah 43a), the
Rambam (Beit ha-Bechirah 10:7), and the Shulchan
Aruch (Yoreh Deah 141:8). This applies only to a
metal menorah. The Shulchan
Aruch adds "even if it isn't 18 handsbreadths
(3 amot) high"; but possibly a small model is
permitted if it's too small to hold a 12-hour
supply of oil.
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