The number 1004 is 100 million (100,000,000), not much time at all for today's computers, while the more naive approach of trying all matchings would yield about two quinvigintillion (2 followed by seventy-eight zeros) computation steps.
Source: wiktionary
In Figure 6.4, you can see that I earned $460 quinvigintillion in the six or so hours that I was away from the game.
Source: wiktionary
In fact, the chance of two irides (yes, this is the plural of the word "iris" — go figure?) being identical is estimated to be one in a quinvigintillion. For the record, that is a crazy huge number—a one with seventy-eight zeroes after it!
Source: wiktionary