The early years of 2017-2018 can be considered the prosperous period for altcoins, during which Btc.d (Bitcoin's market share) dropped from 99% to 36%. Those who experienced that period witnessed tremendous growth, with some altcoins increasing by 100, 1000 times. However, this growth was accompanied by scam projects, which eroded investors' trust. In 2020, amidst the financial market collapse due to COVID, Btc.d regained its highest market share at 72%, and then capital flowed back into altcoins. In just 5 months, Btc.d fell from 72% to 39%, witnessing strong growth in altcoins from the bottom, especially meme coins during this period. The market entered a winter phase, and Bitcoin's market share temporarily increased back to 67% before dropping 7% to around 60%. Looking at the chart, we can visualize the movement of Btc.d in detail, as it moves within a triangular pattern, with the amplitude of fluctuations narrowing towards the end. Conclusion: The altcoin season is becoming less attractive. If in the coming months Btc.d drops to around 50%, consider converting altcoins to Btc or Usdt. Some analyses are based on personal opinions and perspectives, not investment advice, and should only be used for reference. Best regards!