Code reuse (the only type of reuse being attempted at the time) was seen as a way to buy hundreds of nails at the hardware store rather than making each nail by hand.
The latter is characterized by the inability to nail down requirements up front, making it necessary to continually adapt and re-estimate as a project progresses.
后者的特征是没有事先明确了解需求的能力，因而需要随项目的进展不断地调整适应和重新评估。
3
Pin a nail on the outside of the door frame and leave a part of protrusion. Making the exposing part of the nail make up the gap between the door and door frame.