v76 · 2026-10-31

• The nine chapters are rewritten in plainer prose, as the lessons were in v72 and v75: long sentences split, the
  reason next to the fact, every term explained where it first appears, and a few skipped steps written out. No
  heading, equation, table, live value or measured number changed.
• Corrections found on the way, in the chapters and the lessons that point at them: a late lidar scan is placed
  from an estimate that lags with it, so the walls smear rather than shift (perception lesson 4 and chapter 3 §7,
  measured headless); a diagonal space-time move takes one step, checked at both ends; velocity obstacles sample 77
  candidates; the chamfer distance errs on the unsafe side and the lethal margin covers it; a radar update leaves an
  ellipse stretched across the line of sight; pure pursuit's short-lookahead oscillation comes from the delays, not
  from lost damping; and the Butterworth damping of LQR holds for any weight ratio when only position is weighted.