One person's data is another person's program. -- "Programming Pearls",

Related:

• One person's constant is another person's variable.
  Alan J. Perlis, "Programming Pearls", Communications...
• The first step in fixing a broken program is getting it to fail repeatedly.
  "Programming Pearls", Communications of the ACM, Sep...
• The sooner you start to code, the longer the program will take.
  "Programming Pearls", Communications of the ACM, Sep...
• Whenever possible, steal code. -- "Programming Pearls",
  Communications of the ACM, Sep....
• One ostrich egg will serve 24 people for brunch. -
  "Programming Pearls", Communications of the ACM, Sep...
• The job's not over until the paperwork's done. -- "Programming Pearls",
  Communications of the ACM, Sep....
• Testing can show the presence of bugs, but not their absence.
  "Programming Pearls", Communications of the ACM, Sep...
• The cheapest, fastest, and most reliable components of a computer system are those that aren't there.
  "Programming Pearls", Communications of the ACM, Sep...
• The structure of a system reflects the structure of the organization that built it.
  "Programming Pearls", Communications of the ACM, Sep...