That picture would make a good addition to the Wiki article on obsolete power outlets,
http://en.wikipedia.org/wiki/Unusual_and_obsolete_plugs_and_sockets
I could upload it to there if okay by you.

At least it's polarized!

The black tandem outlet on that page looks like it'd be able to nicely seat two wallwart transformers side by side.

At last the answer to the question I've wanted to know for a long time; as I've suspected all along, the Australasian three pin plug has the same pin spacing as the 'obsolete' US counterpart on which the design of it is based.

I have one of those obsolete US counterparts (it has a UL marking on it) in service in my mom's house, wired to 240V 60Hz, so it can feed some of my radios in my collection: Foreign radio sets in my radio collection

When did the whole polarized plug thing come about? I find it hard to believe that is from 1928. Because I have a old lamp I got a garage sale a Nice old floor Takes the big Street light style bulbs on the top and has 3 sockets around the edges that take a standard bulb. and the plug is not polarized neither is the plug on my Moms old iron or Stereo. Oh I rewired that lamp because it had cloth cord which was in very bad shape. and the plug was also missing the deadfront Cover (It was one of those plugs where you can see the terminals while looking down at the prongs)

Recepticals were probably polarized way back then. Plugs on appliances and lamps didn't begin to be polarized until the later 1970s, at least what I've seen. Shortly after that two wire extension cords began to be polarized also.

I have one of those 5-outlet receptacles. I have other ones that are 3-outlet. They are all integral with the plates, like that one.

You can't plug very much into the 5-outlet one, unless they are super skinny plugs.