Pen that lets users doodle in the air

    The world's smallest 3D printing pen will let users draw complex designs in mid-air.
    Designed to be comfortable to hold and easy to use, the pen will be powered by a USB port and take only a moment to heat up. The plastic filament used to create the 3D object will be inserted into the pen's upper end, where it will move through a special mechanism to reach the hot-end nozzle. The nozzle will both melt the filament and cool it down, allowing the user to draw complicated, 3D structures in the air.