Constructional apraxia is defined as an inability to physically or mentally combine parts of something into a coherent whole. It's sometimes considered a disorder of gestalt, in that afflicted patients can (metaphorically) see the trees but not the forest; For example, a person with constructional apraxia can't build things from models, can't put together one of those pressboard bookcases that you get from Staples, and can't copy designs. This deficit is a relatively common consequent of damage to the posterior right hemisphere, particularly the parietal lobe, though it may also occur with left hemisphere damage.