There’s also a history of using ‘X’ as the designation for eXperimental planes, e.g the X-15. I always assumed that was the inspiration for the use in tech bra

There’s also a history of using ‘X’ as the designation for eXperimental planes, e.g the X-15. I always assumed that was the inspiration for the use in tech branding like Google X - conjuring up images of skunkworks, etc.