Sidewalks

Many of the buildings in Taipei actually have 2 sidewalks. There is the one closest to the road, which is called the 人行道(rénxíngdào) or "pedestrian walk way". The other is the 騎樓(qílóu) or "overhang".

The one closest to the road(the renxingdao) is maintained by the city and usually is paved with cement blocks. The one under the second floor eaves, (the qilou) is owned by the storefront owner and is their responsibility.

 In some parts of Taipei you can walk when it's raining without an umbrella because there are so many qilou. The qilou is usually paved with tiles or stone and is a chance for the owner to distinguish themselves. 

The pattern can be good or bad. Usually for hotels it is the first thing a visitor sees so it sets the first impression.

But sometimes it seems to be a collection of remnants from other projects.

I think one of the reasons that the sidewalks are done in this way is simply because the streets are narrow and it would be hard to get a cement truck into place to pour cement. But on some streets, like
Civic boulevard it is done.