the product of thinking has novelty or value, either
for the thinker or his/her culture.
the thinking is unconventional, in the sense that it requires
modification or even rejection of previously accepted ideas.
the thinking requires high motivation and persistence,
taking place over a considerable time span (continuously or
intermittently) or at high intensity.
the problem as initially posed was vague and ill-defined,
so that part of the task was to reformulate the problem itself.
Newell & Shaw (1962), from R.L. Glass Software Creativity 2.0