She closed her laptop and stepped outside, noticing the distribution of birds on the telephone wire as if it were a data sample to study—where might clustering suggest communication hubs? What variance did spacing show? The day felt like a gentle experiment waiting to happen.
A high-quality PDF (think Casella & Berger, Hogg & Craig, or Wackerly) is a time machine. It forces you to slow down. You cannot skim a lemma. You cannot "Ctrl+F" your way to enlightenment. You have to read the line: She closed her laptop and stepped outside, noticing