Notes 4

• Reading Howard Spodek's "The World's History, 5th Edition" Jan 1, 2026
• Reading "The Ruby Programming Language—Chapter 1. Introduction" Jan 1, 2026
• 读小平邦彦的《微积分入门》（修订版） Dec 29, 2025
• Reading "The Ruby Programming Language" by David Flanagan and Yukihiro Matsumoto Dec 26, 2025