[nonother]

I don't have any pictures to show you, but I think I can help you out on numbers 2 and 3.

2. The trick with getting enough friction is having enough force on the softballs. Remembering that friction comes from both the coefficient of friction and the force being applied. You might be able to increase the coefficient of friction by changing the surface of the treads, but that's likely not worth it. Instead you need to increase the tension of the system so that the treads exert a lot more force on the balls. As a result the friction will increase. The way to do this is to make the tread loop as tight as possible and then stretch it outwards and insert in one of the tightener pieces (the large black and grey ones) that come with the tank tread kit.

3. I think you get how to build it so I won't explain that part. The way it works is to think of each wheel as a vector force. Moving in one of the cardinal directions (straight up, down, left, or right) is trivial as you just power two of the wheels and leave the other two unpowered. To move up and to the right (say at a 45 degree angle) you need to equally power the side wheels to go forward and the front and back wheels to go to the the right. Unless you want to do vector addition on the fly in your head, you'll want to program the robot to make it much easier to drive. I know there is MPLab code already written for a simple holomonic bot floating around on the forums.

I'll see if I can dig up any pictures.