Third Grade Line art, i mean Photoshop Line Art

For this assignment we had to draw five 5" x 7" black and white line art illustrations, BUT WAIT!  We had to draw them in Photoshop with a tablet, or a mouse, whichever was working better.  I did a few with the tablet and a few with the mouse.  I have worked with tablets before but it still takes some getting used to.  There was a lot of command-z"ing" because i often found the line i was working with would not do what i wanted it to, this resulting in a third grade quality.  I do enjoy working with a real pen and paper better, however i still found this exercise interesting. . . . and frustrating.  Below are a few of my favorites.  The pipes were done with a mouse and the building was done with a tablet.  I got really drawn into some detail with the building then i found it impossible to draw the left side!  I hinted at the wall.

It's the back of OP!

I passed the 3rd grade with this gem here...