Buildings are another important element to a good street. Spacing of buildings, much like tree spacing and sidewalk and street widths, give the street definition. There are boundaries and proportions that make the street comfortable and aesthetically pleasing on a human scale. Buildings that are poorly spaced are not only inefficient uses of space but also may give the feeling of being exposed and disconnected. There is then doubt about where one is. Many smaller buildings rather fewer large buildings give a sense of scale. Smaller buildings are on a human scale; there are many different reference points. In addition many buildings allow for the possibility of greater diversity. The super block, which became increasingly popular in the 20^th Century does not allow for as much diversity. The super block does not have residential zoning. This makes the street and the community limited. Generally there are fewer separate buildings and therefore fewer places to go and experience. More buildings mean more contributors to the street and this adds to the feeling of continuity and definition (Jacobs 1995, p.297). Buildings also need to be in proportion to the street; buildings that are too tall will not let in enough light and will also give a feeling of vulnerability. Height to horizontal distance ratios of between 1:2 and 1:4 are generally proportioned correctly for most streets (Jacobs 1995, p.279-280). These ratios occur with street heights under 100 feet. There are certain characteristics that need to be accounted for on each individual street like street widths and building heights, tree height and widths, street length and topography (Jacobs 1995, p.279). Buildings should also be aesthetically pleasing. Beauty is an added attraction to a street; it makes people want to be there and gives the residents of the city something to take pride in. People want to live, shop, and work in a beautiful environment.