Stack Exchange network consists of 175 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.
Not 100% sure if these are elongated or round seats. (I don't have physical access to verify.)
Those are round. They are not interchangeable. Elongated seats go on elongated toilets and vice versa.
How long is the seat? Here's a guide: