Spandrel
In 1979, Lewontin and I borrowed the architectural term “spandrel” (using the pendentives of San Marco in Venice as an example) to designate the class of forms and spaces that arise as necessary byproducts of another decision in design, and not as adaptations for direct utility in themselves [1]
A spandrel[1] is a roughly triangular space, usually found in pairs, between the top of an arch and a rectangular frame; between the tops of two adjacent arches[2] or one of the four spaces between a circle within a square. They are frequently filled with decorative elements.
The idea was adopted in biology
In user interfaces this happens too! Often we make big significant changes for happy flows, and get those spaces in between.
In design, spandrels are sometimes just byproducts of other decisions. Sometimes it is just about availability of new spaces or resouces. Sometimes it is adaptive reuse.
Skeuomorphism can be used to de-emphasize the technology in favor of the utility.
