Definition
This idiom is used to express that all things of a particular kind are very similar and lack significant differences.
大同小異
These chain hotels are all the same; if you've stayed at one, you've stayed at them all.
這些連鎖酒店都一樣；如果你住過一家，就等於住過所有了。
I think these superhero movies are all the same; if you've seen one, you've seen them all.
我覺得這些超級英雄電影都一樣；如果你看過一部，就等於看過所有了。
The designs of these products are all very similar; if you've seen one, you've seen them all.
這些產品的設計都非常相似；如果你看過一個，就等於看過所有了。