And then around 2013, obviously the holy grail when it comes to implantable system is to understand how small of a thing you can make, and a lot of that is driven by how much energy or how much power you can supply to it and how you extract data from it. At the time at Berkeley, there was this desire to understand in the neural space what sort of system you can build to really miniaturize these implantable systems. And I distinctively remember this one particular meeting where Michel came in and he's like, "Guys, I think I have a solution. The solution is ultrasound." And then he proceeded to walk through why that is the case. And that really formed the basis for my thesis work called Neural dust system, that was looking at ways to use ultrasound as opposed to electromagnetic waves for powering as well as communication. I guess I should step back and say the initial goal of the project was to build these tiny, about a size of a neuron, implantable system that can be parked next to a neuron, being able to record its state and being able to ping that back to the outside world for doing something useful. And as I mentioned, the size of the implantable system is limited by how you power the thing and get the data off of it. And at the end of the day, fundamentally, if you look at a human body, we're essentially bag of salt water with some interesting proteins and chemicals, but its mostly salt water that's very, very well temperature regulated at 37 degrees Celsius. And we'll get into how, and later why that's an extremely harsh environment for any electronics to survive. As I'm sure you've experienced or maybe not experienced, dropping cell phone in a salt water in an ocean, it will instantly kill the device. But anyways, just in general, electromagnetic waves don't penetrate through this environment well and just the speed of light, it is what it is, we can't change it. And based on the wavelength at which you are interfacing with the device, the device just needs to be big. These inductors needs to be quite big. And the general good rule of thumb is that you want the wavefront to be roughly on the order of the size of the thing that you're interfacing with. So an implantable system that is around 10 to a hundred micron in dimension in a volume, which is about the size of a neuron that you see in a human body, you would have to operate at hundreds of gigahertz. Which number one, not only is it difficult to build electronics operating at those frequencies, but also the body just attenuates to that very, very significantly.