When the obvious solution fails we must examine what assumptions have proven false.
When the obvious work completes we must set new goals before continuing.
When the next step is obvious and the obvious solution works then development proceeds at a predictable tempo. When the tempo pauses, it is enough to ask, what happened to the obvious solutions?
When the way towards goals is not obvious we must select simple experiments to inform our intuition.
When there is disagreement on goals we must expand the realm of discourse and deliberate at that level.
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In each of these cases we will enter into a mode of problem solving unlike the high tempo work and unlikely to be predictable until the tempo resumes. It would be foolish to ask, when will work become obvious again? That wouldn't be obvious.
We shouldn't be concerned when these tempo pauses occur because they each represent a highly leveraged decision-making period. Learn to savor these moments and use all of the creative talent available to best advantage. See Loss of Tempo Signal
See Understanding Interruptions through reflection.
Contrast Prioritize Tempo with very small commits.
See Gary Klein Videos for similar case analysis.