"Without electronics" except for the computer devices that have to be dedicated to monitoring for the back-scatter created by the 3-D printed objects and translate it into something meaningful.
Yeah ok I understand that it doesn't have a memory. But you can still sort of "query" the current state of a device that is always broadcasting, like a flow or speed sensor.
You could presumably use existing devices for that, but it would require making a serious software change - in particular, you'd have to alter the radio driver to listen to and recognize backscattered signals (instead of rejecting them as noise).