John's personal interests outside work, for reference/context rather than active project tracking.
• Retrocomputing — Z80 and RC2014 hardware; see Z80 Sudoku Challenge and Z80/instruction-set.
• Science fiction — Ringworld, The Hitchhiker's Guide to the Galaxy.
• Physics.
• German language learning.
• Folk music.
• GPS/location tracking — see using-gps-data and OwnTracks.