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Jenga Pistol (woodgears.ca)
278 points by antr on Dec 24, 2014 | hide | past | web | favorite | 24 comments

If you haven't seen Mattias' website before, you should take some time to look at all of the other cool stuff he's built:


This guy is awesome.

I especially love his marble machines. They're absolutely mesmerizing.

His Lego domino row building machine is pretty neat too. It does its job pretty well, with only a few Lego blocks used. http://woodgears.ca/domino/index.html

Mattias has a great youtube channel. Highly recommend subscribing. https://www.youtube.com/channel/UCckETVOT59aYw80B36aP9vw

I don't do any woodworking but love to watch his videos.

Inspiring guy. He seems to make his money from selling his woodgears software program, plans for some of his woodworking projects and from Google for being a Youtube partner.

Pretty cool.

What's really cool is that this is his hobby. He was an early BlackBerry employee. He retired to do this full-time.

mattias' approach has really influenced how i think about software engineering. not entirely surprising considering he is also a software engineer. i think his youtube channel is really worth checking out. he has even invented several new, amazing tools, like the "pantorouter" for cutting perfect mortise and tennons (among other things) with a router. https://www.youtube.com/watch?v=8wZ1v4PIsYI

the way he solves, and even identifies, the problems in the woodworking domain are, i think, very instructive for how to think about some aspects of software design.

My 15 year old brother made one of these a couple of years ago. He saw a video that demoed it with the plans available for $5 but he looked at the video and went and made it from mind.

It was so powerful, almost hilariously so!

He actually said on Facebook earlier: "I made one of these before it was cool."

I've been half-joking with friends about going out to the desert and playing "gun jenga". Good to know the physics are in our favor :)

With an actual firearm and bullets, it might not be; bullets don't have a lot of mass.

For this purpose, isn't it force, not mass, that matters?

F = mv^2, so the velocity of bullet is a very large factor, especially when the terminal ballistics allow for most or all of the energy to be dumped into the target.

And the history of cartridges, the ability to "reload", make your own custom load, and the ability to stand off to let air resistance bleed off velocity, means you'd likely be able to apply the exact amount of energy you'd want.

No, impulse is what matters here, and that is mv.

And force is ma. You must be thinking of energy.

Yeah, I'm thinking of energy, but in this case I'm assuming the terminal ballistics will dump all the bullet's energy into the block that's hit (that it won't penetrate all the way through the block). Impulse is force over a period of time; in this case, doesn't it equals the same thing?

What you have to think about is the force of the hit, the friction and inertia of the block and the material properties of wood and metal. This would let you calculate the impulse of the hit, which should let you work out if the block will slide out before expanding much vertically as the bullet trashes it.

If you're interested in this kind of stuff, this German guy has a great channel on Youtube: https://www.youtube.com/user/JoergSprave (his slingshot cannon is especially impressive)

It's kind of interesting how the dynamics of the game completely change with the pistol. Since you can get rid of entire rows now, you have rows of same orientation stacked upon each other all of a sudden.

You can get rid of entire rows without using a Jenga pistol, too. You just have to be fast.

Struck me that it's like a physics flash game (a la Blosics).

This just in: life imitates art.

Have I told you about the Jenga block catcher© I'm building?

What a creative person!

A Jenga shotgun to be used with those oversized sets would be far more impressive. lol

Wouldn't work. Shotgun shells spray in a cone shape.

If you are using shot, use a slug and it would be fine.

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