Good questions! I had two starting points: a) I won the VIC20 as a prize in a science competition age 13. I started with BASIC, discovered PEEK and POKE, and t

Good questions! I had two starting points: a) I won the VIC20 as a prize in a science competition age 13. I started with BASIC, discovered PEEK and POKE, and then saved up my pocketmoney for the Assembly Language cartridge. I was intrigued by the ROM and copied the entire disassembly into exercise books to figure out how it worked (printers were too expensive back then!). I reverse engineered the arithmetic routines, from which I discovered floating point representation's mantissas and exponents. b) I expect the graphics transformations came from Mathematical Elements for Computer Graphics, by David Rogers and James Adams (McGraw-Hill, 1976), which I would have found in the library at my mum's work. Her work was opposite my school and I often killed an hour or two in the computer section reading back issues of Byte magazine waiting for her to drive me home. I think that was the book because prompted by your question, I just found Rogers' 1988 update Procedural Elements for Computer Graphics in my bookshelf. The price sticker inside the cover says '1/89 $41.99'. That shows I bought it with the money earned from my first university holiday job in Dec 1988/Jan 1989. That was at the research labs of BHP Billiton, the Australian mining company, where I designed and built the electronics for a 32-channel channel data logger for a steel rolling mill, and taught myself C and wrote the data acquisition and display software.