There is a famous drawing of the menorah by the Rambam in his peirush mishnayos (commentary to the Mishna); this is what it looks like:
However in the Rambam's commentary as printed in my gemara (Greenwald shas) it's depicted like this:
Why would they make the menorah round if the Rambam's actual drawing is straight? In addition, the Rambam son(Rabbeinu Avraham) writes in his peirush on chumash (Terumah 25:32 ) that the menorah is straight like his father drew and not round like others depict.