1. By Jesus only.
Modeling the head.

2. Instructions
Get a suitable model of a head. -
See this video -
Takes time

3. 3-D print history
Three-dimensional printing, also known as additive manufacturing, is the process of using additives to form solid 3D objects of virtually any shape from a digital model. This is achieved using specially formulated additives, such as plastics, that are formed into successive layers of material typically laid down on a platform in different shapes. 3D printing is uniquely distinct from a more traditional 3D sculpting technique, which relies on the removal of layers (subtractive manufacturing) to produce a three-dimensional object.

4. Why is 3-D printing useful
3-D printing is going to impact so many industries, such as automotive, medical, business & industrial equipment, education, architecture, and consumer-product industries.
With 3D printing, surgeons can produce mockups of parts of their patient's body which needs to be operated upon.

5. How is it done. Here is a link to 3-D printing video
Some steps

6. Finished