Bitcoin has been around for 16 years, but the 4-year cycle has never changed. Why did Satoshi Nakamoto design the 4-year cycle? 1. Inevitable result of code and mathematics: To ensure the total supply is absolutely capped at 21 million coins, it was necessary to set a rule where the block reward halves every 210,000 blocks. The time it takes to mine 210,000 blocks is roughly 4 years. 2. Economic design inspired by gold mining: It mimics the increasing difficulty of gold extraction. In the early stages, high rewards attract miners to secure the network. The mandatory supply cut every 4 years creates extreme scarcity. 3. Aligns with macroeconomic cycles and human emotional metabolism: 4 years coincides with the rhythm of global macroeconomic liquidity cycles (like the Federal Reserve's cycle). 4. Resonates with celestial and calendar rhythms: 4 years is the smallest complete cycle that resets calendar errors after Earth's orbit and a leap year. It also resonates with the orbital cycles of Jupiter and Venus, aligning with the natural laws of rise and fall in all things. But everyone says this year is different, this time is different. Is it more likely that things will stay the same, or that this time will truly be different?