where did the on off symbol come from
Power symbol The well-known on/off power symbol was the result of the logical evolution in user interface design. Originally, most early power controls consisted of switches that were toggled between two states demarcated by the words On and Off. As technology became more ubiquitous, these English words were replaced with the universal symbols line "|" and circle "o" (typically without serifs) to bypass language barriers. This standard is still used on toggle power switches.
Anarchist symbolism Anarchists have employed certain symbols for their cause, including most prominently the circle-A (Ⓐ) and the black flag (⚑),[1] although anarchists have historically largely denied the importance of symbols to political movement.[2] Since the revival of anarchism around the start of the 21st century and concurrent with the rise of the anti-globalization movement, anarchist cultural symbols are widely present.[3]