automatic switch

does anybody have a idea how to create an automatic booleon switch? I want i
t to switch on and off every 20 seconds

Hi Jack, -create a while loop with a shift register- init the shift register
 with a FALSE constant- wire from left SR to right SR, insert a NOT function
 in the wire- create an indicator for the wire- place a delay function in th
e loop, wire 20000 to itRea
dy...

it worked.....thank you so much!