hostile architecture

Have you tried to find a place to sit down in a public space and noticed that the benches are all curved, have arm rests at regular intervals, the seat dips in a peculiar way that is rather uncomfortable?  These are not fashion statements or examples of the latest theory of ergonomics.  Rather they are designed to make the seats impossible to sleep on, thus preventing homeless people from using them as a bed for the night.

Similarly sheltered corners or dry refuges under awnings can be spiked or made inaccessible with bars, or paved with rough stones that make any lasting visit very uncomfortable.

This is called hostile architecture with the hostility being solely directed towards the homeless in our cities.