Question about graft growth

[Driver]

After HT most docs give a sheet showing how many 1s,2s,3s, and 4s the pt had transplanted.

Do all these grafts start out with one hair being produced and twos going on to make two hairs at a later date or do twos always make two hairs, threes always makes three hairs, etc.?

Also, if grafts that produce multiple hairs start at producing just one hair, when do they start to form a multiple hairs?