I drew this doorknob and deadbolt while sitting on my porch. It is the door into my living room: one half of a set of french doors. I was kinda happy with this one; maybe because I have installed so many of these things, I have a certain knowledge about them.
As a carpenter-cum-contractor, I have always used the proper installation of a door as a metaphor for the way I try to conduct all of my work. If the door is hung correctly, then everyone will use it as intended and pass through it without notice.