The stock market moves in patterns that occasionally repeat themselves for a while and then vanish, a feature common to unpredictable systems. Even if the pattern holds, there is nothing to prevent the market from tanking and then recover to produce a strong 17-year average return by 2026. The 20%-plus Crash of October 1987, for example, happened five years into the tenfold stock rise of 1982-2000. The cycle described above does not say much about where the market may be this year or the next, but those who wonder about the long term may find the idea of being in the initial stages of a long rally quite exhilarating.