Playplax, another toy from my childhood, was designed in 1966 by the brilliant British industrial designer Patrick Rylands. It’s in the permanent collection of the V&A Museum in London. Thanks to Fraser for actually finding it online, after I failed to (see his comments here). I had this toy as a child and have since spent years and years trying to find out what it was. More on Patrick Rylands at Wary Meyers.
You can order Playplax at the source, Portobello Games in England, or from Amazon.co.uk. They’re on Twitter too. It’s unfortunate that this amazing thing isn’t being distributed in North America. UPDATE: commenter below notes that Playplax is now available in North America here.
Rylands also produced the famous bird and fish bath toys enjoyed by me and most of my friends as kids: