When designing details, consider if and how you want to have decoration applied to those details.
Some schools of architecture such as [link blocked]modernism reject decoration that is applied for decoration's sake. Instead, beauty is sought in materials and forms that perfectly serve their function.
In other [link blocked]styles of architecture, a great deal of attention is paid to decoration that is applied to surfaces and forms. This desire for decoration comes out of the fact that people like to adorn what they adore, to elaborate their art, and to decorate and embellish the fine details of their work.
These chimneys on Antonio Gaudi's Casa Mila are an excellent example of applied decoration that also melds beautifully with function. The chimneys are shaped into whimsically decorative heads, while the eyes and mouths form functional openings of the flues.
Decoration can be particularly effective when confined to one area or against black background. The [link blocked]contrast that this creates helps to put a further exclamation point on the decoration.