I've watched friends and guests toying with these little pyramids. Often, they try to stack them to form a larger pyramid, but it just doesn't work.
It occurred to me to design a simple part that can be combined with the test parts to build a larger pyramid, like the one pictured below. It's sort of like a "missing piece" for the larger pyramid.
In fact, my extra piece looks just like the standard test part...at first glance. It's foldable sheet of four triangles, like the test part, but the edges are chamfered at different angles and there are other differences.
This shape forms very-narrow channels during printing, which has the disadvantage of leaving hair-thin strands of support material that must be peeled away. I've successfully cleared the waste material from every part I built so far, but it takes a bit more effort than usual!
I added a triangular hole to the new part to help distinguish it from the ordinary test parts. As shown here, it doesn't quite fold like the regular test part.
I soon found the hole was a convenient feature to help disassemble the parts, so I designed a version of the standard SD300 Test Part with a round hole to reach inside and pop it apart. A complete puzzle set consists of one Mizzing Piece part (triangular hole, at right) and five standard test parts or my equivalent (round holes, at left).
I posted the Mizzing Piece STL at Thingiverse
There is another way to make larger pyramids without using a custom part:
ReplyDeleteInstead of folding each piece, you can attach 3 together to form a larger pyramid. A forth triangle forms the bottom.
You can keep doing this instead of using a bottom. The pyramid grows like Pascal's triangle on each side. Top layer is 3, next layer is 9 (3 per side), and so on. I currently am up to 3 complete layers with a forth in progress and a total of 28 test models so far.
True enough, I probably should have mentioned the 4-piece pyramid just for the sake of clarity. Test parts can be assembled into a variety of shapes, especially if the user 'cheats' by folding some of them inside-out. (Try building the shapes illustrated at http://www.mefferts.com/puzzles/jpmsol.html for example.)
ReplyDeleteBut of course my goal was to impose a different challenge; it's not merely how-to-build-a-pyramid, but how to employ all six pieces to do so. And because I was inspired by the 'stacking' behavior, I aimed to build multiple smaller shapes that could be stacked to form such a pyramid.
Hi Scott !
ReplyDeleteI wonder if you could build some of my puzzles since I haven't got my printer yet.
George
inzane-thingz.com
YouTube inzane thingz
Could you share these files (preferably STL format)? I'm just starting and I need a good test model for my SDview 3.00. Thanks!
ReplyDeleteThe files can be downloaded from Thingiverse at the link after the last picture.
ReplyDeletehttp://www.thingiverse.com/thing:3545