That looks like an interesting book .   It is . It ’ s got pictures of interesting building from all over the world , with brief descriptions of how they were build , their purpose , and so on .   There are the pyramids . It ’ s easy to see how they got that name ! they don ’ t have smooth sides though .   They don ’ t now , but most of them did originally . There ’ s picture of the pentagon in the united states . It ’ s very distinctive with its five sides .   Look at that cylindrical office building . I ’ Ve never been seen one that shape before .   Yes . Usually only TV towers are cylindrical in shape .   TV towers are usually thicker at the bottom than at the top . They ’ re not perfectly cylindrical . 