There is sometimes a blurred line between renovation, adaptive reuse, reconstruction and facadism. Sometimes buildings are renovated to such an extent that they are "skinned", preserving only the exterior shell, and used for purposes other than those for which they were originally intended. While this is equivalent to facadism, the difference is typically the retention of roof and or floor structures, maintaining a credible link to the original building. In contrast, facadism generally involves retaining only one or two street facing walls for purely aesthetic and decorative purposes. Facadomy is a practice in postmodern architecture reaching its peak in the latter half of the 20th century. The setback or podium architecture technique gives an illusion of integrity to the original building by visually separating the old from the new, helping to mitigate farcical effects such as the floors and windows not lining up or a dramatic clash of styles.