Growth Modeling Device is a kinetic installation by David Bowen. The machine uses lasers to scan a plant, in this case an onion, from 3 different angles. That data is then used in real-time by a fuse deposition modeler, to create a plastic model of the current state of the plant. This process takes place every 24 hours, but each time the plant is scanned from a different angle. In the end you have several models illustrating the growth of the plant. You can see a video of this installation here.
This is actually a little similar to an older project of David: Growth Rendering Device.