It is also contemplated in this embodiment that {HEAD ~ the pen cartridge} may be extended as a result of a pressure applied to the edges of {TAIL ~ the housing} 
It is also contemplated in this embodiment that { HEAD ~ the pen cartridge } may be extended as a result of a pressure applied to the edges of { TAIL ~ the housing }
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL