What is a scissor gear?

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Ok, so I'm living in the Stone Age. My bike has a carburetor. Crikey, I've still got a CRT television. I don't think I'd ever heard of a scissor gear before I started reading about the Milwaukee Eight.
A scissor gear is actually two gears with offset teeth. Like a lot of things, it's easy when you know how. The offset is accomplished with either tension springs, compression springs or bolts.
What's in the M8, mate?

https://youtu.be/w_1NxcnoB0s

[Rockout Rocker Products]

Here ya go.... http://harleytechtalk.com/htt/index.php/topic,93221.0.html

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Yeah, no worries, seen that. That pic looks like more than one piece. Is that a directional arrow on the thinner row of teeth?

The counterbalancer scissor gear looks like it could be one piece. I guess a solid piece could be manufactured with offset teeth.

[jbexeter]

also known as "anti-backlash" gears, thing is in engineering you always trade one thing for another, you trade less backlash for more wear.

accelerating and braking a heavy counterweight has to be up near the top end of loads that I am aware of for anti-backlash gears, more common in camshafts and suchlike with almost no rotational mass.

[Breeze]

I just learned something. 

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The counterbalancer scissor gear looks like it could be one piece. I guess a solid piece could be manufactured with offset teeth.

Scratch that, can't be one piece. It would defeat the purpose. Might as well just have fat teeth.
The gears have to "scissor" to take up the free play or backlash. The action can also be performed with oil or air pressure.