When my son was a child, he once walked with his head down and picked up 10 yuan. Later, for a while, he always kept his head down when walking, and he was actually asked to pick it up again. So he refused to listen no matter how much I tried to persuade him, hoping that he could still pick it up. money until he hit his head on a tree.

Occasionally "lowering his head" resulted in the result of "picking up money", and "picking up money" encouraged him to increase the frequency of "lowering his head", which would inevitably increase the probability of "picking up money".

Initial investment - return - incentive mechanism - automatic repeated investment, causal loop, mutual promotion, this is the principle of "closed loop". "Walking with your head down to pick up money" is probably the first "business closed loop" formed in my son's life.

All successful and sustainable business models must form a "closed loop". #BTC