Did you know that the symbol for power / standby mode used on  most electronics today has existed since 1973?  At the time, it was included in a standard created by the International Electrotechnical Commission (IEC) for use on various electrically powered equipment.  Originally this symbol was meant to be used for  “Standby” mode.  It wasn’t until 2004 that its current more generic “Power” meaning was adopted in a standard released by the Institute of Electrical and Electronics Engineers (IEEE).  The symbol is composed of two superimposed numbers, 1 meaning on, and 0 meaning off.