THE SOLAR SYSTEM
eight planets · size, distance, year and day
Free
MORSE CODE
26 letters and 10 digits · dot, dash
Free
BICYCLE CLASSES
frame, wheel by ISO 5775 and handlebar — three signs of a class, and what the frame is rated for
Free
CAR CLASSES
segments A to F by length and bodies by box count — how to name any car you see
Free
MOTORCYCLE CLASSES
rake, trail, wheelbase and seat height — six classes drawn at one scale
Free
THE RACING LINE
one corner, three apexes, the time computed
Free