The first distinction is between design and manufacture, and the second is between tools and materials. It is the dissolution of these categorical boundaries that is a indicator or symptom that craft-work is taking place. The first quality that distinguishes craft-making is the dissolution of the boundaries between design and manufacture. A designer makes things, typically, his or her making process is complex. Because there are more variables than can be represented in a finite model, the parameters of a problem often emerge during the attempts to build the solution.
Some attempts fail, but reveal previously unrecognized constraints.
In practice, this cycle can be extended beyond a single problem. In fact, most software is increasingly made by modifying or recombining the actual material of a previous piece of software, as a building may be altered for new use. This process is more like craft than engineering. Engineering is the rigorous application of technical knowledge. The difference is that in a craft process, before problem solving can begin, problem setting must occur.