Let me show you an example of the assist. Sketch understanding system and operation. I'll draw a simple mechanical device and show you that. The computer understands what it is that I've drawn. I'll start by drawing a simple hill. I'll anchor it to the background. I'll put a little cart on the hill. Give it wheels pin the wheels to the frame with some axles and then indicate that. I want gravity and now if I draw on this on a piece of paper and shown it to you you'd understand what it is. It was about to happen. I want the computer to be able to understand what's going to happen as well and I can simply push the Run button and it produces the expected simulation now. I'm going to run that again and I want you to pay attention to how the car moves as it runs down the hill. You'll see that it wobbles just a little bit because I haven't drawn the axles in the center of the wheels. Now one of the nice things about an online environment is we can have the advantage of having it feel like paper and yet be able to do things that are not possible to do on paper for example. I can take this and decide that I don't have it in quite the right place and what I'd really like to do is move it just a bit and put it over here and I'll run the simulation again with my new conditions and finally we'll go back there one more time and this time what I'd like to do is make the simulation a little bit more interesting and a little bit more complicated. We'll add a speed bump and anchor it to the frame and we'll add a pendulum and now let's see what it is that our system is going to do in operation. It still manages to make it over the speed bump and head on down the hill. Now let me try another device this time. Something a little more similar to the kind of thing that might happen in a real design environment here you see. I've circled all my previous drawings and I'm just going to get rid of it by saying scratch that out. Let's try a simple little marble game the kind of thing that we might have in a real design environment.

I'm going to draw a collection of boards for the marbles to run down. I'll anchor them to the background. Put one more board down here and let's give them a cup fall into and just to make it interesting. Well anchor the cup with a couple of Springs. Put some marbles up here okay now. Let's see what this does oops not quite. Let's go back to the drawing board literally and see if we can't fix things. Suppose we take this shelf and move it a little bit and then let's take this shelf over here and move it a little bit and now let's try the device again. Ah still missed one more shot at it. This time. Let's try grabbing the cup changing. Its location all right we've succeeded and what I wanted to show you is. We have a design environment. The beginnings of a powerful design environment that allows the kind of natural and familiar style of interaction.