Think of the shear tool as kind of a triangular magnet too. It allows you to shift points in increasing or decreasing amounts, uniformally.
Wow, that made no sense.
If you made a stack of say, 8 points above each other, you could take the shear tool, right drag it to size along the height of the points. Then when you left drag watch what happens, and how the points move in relationship to the guide you made. It is helpful to have the numeric panel up, to change its axis or effect.
I think if you messed around with that you'd get the idea. I find the shear tool very helpful and find myself using it on a semi-regular basis.
Even though I have done the McLaren tute, I don't remember how shear is used. I do remember that a lot of times I used my own means to accomplish whatever Phil was doing.
Hope that helps.
