This book made me understand pointers. As I read it, I followed along building all the circuits in Logisim [1] from half-adders to latches to multiplexers all the way up to a full CPU.
Many will probably recognize the author, Charles Petzold [2], from his Windows programming books.
https://www.amazon.com/Code-Language-Computer-Hardware-Softw...
From binary to a full computer