According to its creator, Guus Oosterbaan:
My ROCK Radio is number two in my cement-audio-series. It started of being a very nice rectangular brick shape. Then I found out that a thick layer of cement shields the radio from actually receiving radio waves. With my “Now it doesn’t work anyway” philosophy, I took a big hammer and created this Flintstones look, and the radio works!
And the promised real rock:
Having a bloody great weekend, peeps.