Can the pieces be arranged in different shapes?

Yes. Each module is separate, so you can line them up as a long sofa, form a corner or use pieces as standalone seats. The shape is limited only by the room.

Does it have armrests?

No. The design is armless, so the ends are open. That keeps the look clean but gives you nothing to lean against.

Is the back high enough to lean your head on?

The back is about 23.6 inches high, which is low. Most adults will not be able to rest their head on it.

What is it upholstered in?

A linen-blend fabric over foam filling. It has a woven look and needs spot cleaning rather than machine washing.

Is it good for a small apartment?

It can work if you use fewer modules, but the full set is large and heavy. Measure the room before committing to the whole arrangement.

How does it compare with a standard sectional?

It offers more layout flexibility but less built-in support and no chaise. A conventional sectional is more comfortable for lounging but fixed in shape.