Parsha Mitzvot: Terumah: Shape of a Synagogue
In 1787 the community of Trieste asked Rabbi Yechezkel Landau whether it is permitted to build a synagogue with an octagonal shape. Rabbi Landau replies that there are no rules regarding the shape a synagogue has to have. It can be built in any form one desires.
“However, all of this I have said in accordance with the strict letter of the law. But I wonder why they should wish to do this. Perhaps they saw something like it in the palaces of princes or in some other houses and wished to copy it. But the truth is that it is not proper for us in our exile to copy royalty and be envious of them. If this was the reason, then I apply the verse, “And Israel has forgotten his Maker, and built palaces.” (Hosea 8:14) It is better, therefore, not to change any of the old customs, especially in this generation.
But if their reason was that there would be more room if the synagogue was built according to these specifications, there is not the slightest fear of an objection. I have to cut short this discussion because I am very busy. – Nodeh B’Yehudah, O”C, #107