An unexpected application of the harmonic series

3-Second Blueprint (English)

1. On a no-passing single-lane road with n distinct preferred speeds, a new traffic platoon forms at each car slower than all cars ahead.
2. Averaging platoon counts across all n! speed permutations yields the nth Harmonic number H_n = 1 + 1/2 + 1/3 + ... + 1/n.
3. Because the harmonic series diverges logarithmically, 10,000 cars form under 10 expected bunches while exit speeds exceed entry flow.