stole the pic from wikipedia, mine actually was way more frankenstein - it was a triple(!) stacker, the middle part was a 3.5" floppy drive, the uppermost third was a 40 megabyte hard drive.   The floppy had a switch in the back soldered in so you could only either use the 5.25" or the 3.5" depending on where it was switched to.   On the sidecarts I had a couple memory expansions, a joystick card, and a hard drive controller sidecar with a big ribbon cable connecting it the hard drive on top.

all this stuff was added over several years, and I got the computer when I was like 10 from an uncle and it was already an antique by the time I got it, I think 486dx's were the top of the line at the time.  I wonder how fast a PCjr could mine bitcoins... 1 hash per day? lol