[jrogers65]

> Unless you lie and tell them that it's something other than a sheet of A4 paper

Which is exactly what has happened here on two counts -

1) it is not a world first - http://www.thingiverse.com/thing:4156

2) it is not a 3D printing pen, it's just an extruder - exactly the same mechanism as that used in a glue gun.

[notmarkus]

1. The item on thingiverse isn't referred to as a 3D pen.

2. Extrusion is the mechanism through which most 3D printing works. In this case, the extruder is attached to your arm rather than to a machine.