Ever wonder about that thing? I received an email from Travis with the following very interesting bit of information on it from Intel, explaining the origin of the power symbol.

They are certainly correct; the symbol is based on binary code, with the ‘one’ or vertical line representing on, and the ‘zero’ or circle representing off, which is what they both represent in code. I’d like to offer a little more clarification about their use and application. The International Electrotechnical Commission (IEC) has standardized this iconography, which makes sense since setting standards is one of their functions. IEC 5007 standardizes the ‘power on’ symbol (the line) with its definition being the symbol represents the equipment being placed into a fully powered state. IEC 5008 indicates the ‘power off’ symbol (the circle) indicates power will be disconnected from the device. There are other symbols as well which can be seen in this one-page .pdf.

You can see these symbols not just in the standard overlapping form presented above, but on almost every power switch, since they are standards. The power-strip below (from England, by the way) and the PC power supply pictured below that both feature the same symbols, just in a different form, but with ‘1’ representing on and ‘0’ representing off.