The Uphill Roller

Today we'll be having a papercraft automata model of a mechanical paradox that was first presented in 1694 through a published recreational volume called "Pleasure With Profit". You may know it by familiar names such as, the Uphill Roller or Double Cone Incline. In it we have a set of shapes which is comprised of a cylinder, a double cone, and an inclined plane. First we tested the cylinder, and it rolled down the incline, just as gravity would dictate. But when we put the double cone on the bottom of the incline, it seems to defy the rule of gravity and it actually rolls up. This kind of thing might look magical to the untrained, but for those of you who where present in class when this was taught or discussed, then you already know the simple explanation to it.

Ok, I'll try to explain it as easy as can be, this apparent paradox is explained by demonstrating the property of the center of gravity of bodies, which tends naturally to move downward. Since the rails diverge, the center of gravity of the double cone, placed on the axis of rotation at the maximum diameter of the device, does not rise when the entire body seems to move up; on the contrary, the center of gravity descends. For a more detailed and better explanation, with video and trigonometry equations - check this page. And here's the papercraft automata version, from our good friend at paperpino.net

Anti-Gravity Double Cone [Download]
Thanks to Cliffy for creating the short video.

Rhino Head Papercraft

Rhinos have been driven to near extinction – the world rhino population has fallen by more than 90 percent in the past 30 years. Whereas 30 species of rhino once roamed the planet, only five remain today, and all of them are endangered. In Africa, only the black rhinoceros and white rhinoceros still exist.

What’s the cause of the rhino’s precipitous decline? Not the habitat loss or food supply disruption that affects so many African animals. Rather, it is man’s relentless pursuit of the animal’s unique horn that poses the single most dangerous threat to rhinos today.

To help educate others, you can go to the African Wildlife Foundation web site for more information on how to help protect and preserve these majestic beasts.

Today we have a rhino head papercraft model from one of our favorite paper engineers, Chan See Lik Paul, who designed this model for 3dpapermodel.com.tw - we've previously posted on his other works such as this Easter Egg and Easter Bunny for Epson Hong Kong.

Rhino Head papercraft [Download]
African Wildlife Foundation [Site]

Update: 06.11.07

Original Chokipeta Wind Waker Link papercraft now available. [Download]

Previous model can be found here and other Choki models here.

Notes: Ron would like to give special thanks to Jen for her work on the first Wind Waker Link pattern and also thanks to Snake for sending in this new model.

Bartolomeu the Troll Sniffer Papercraft

Arf! arf! arf!, said Bartolomeu the papercraft dog. He must have found a live one, go on Bart, bark at those trolls. Bart is family friendly and easy to build, you'll have no problems assembling him, quick and simple to end the weekend. Have Fun!

Bartolomeu the Dog [Download]