This is a pretty straightforward mod - it adds 24 new variants of Carved Pumpkin and Jack o'Lantern.
Using Shears on a standard Carved Pumpkin / Jack o'Lantern will change them to these new variants, shown here:
Continue using Shears to change the face. Durability will not be used!
Sneak-using Shears will go "back" one carving, in case you overshoot.