Triple Check Knit

Today we’ll take a break from digital 3D design and do some good old-fashioned analog knitting. Here’s a stitch we’ve been working with recently, in progress as part of a simple scarf:


If you think there’s something weird about that stitch, you’re right: If you look across each row you’ll see that… there really aren’t any rows? The stitches kind of zig-zag up and down as you move from one side to the other.

The really cool thing about this stitch is that it is completely reversible, and in fact looks exactly the same on both sides:


So what is this crazy stitch, and where did it come from? We call it the Triple Check, and it’s a stitch we made up to solve a design problem. Maybe it’s new, maybe it isn’t; we aren’t sure yet, although we haven’t been able to find anything like it on the web or in our knitting books. If you’ve seen this stitch before, please let us know!

Designing by Deduction

Our design problem was to find a simple knit stitch pattern for multicolor reversible scarves that we could knit during math talks and committee meetings. Specifically, we wanted a stitch that would satify all of the following conditions:

  1. Reversible, preferably identical on each side
  2. Uses multiple colors but NOT floats, double knitting, or carrying more than one strand of yarn at a time
  3. Must be a simple stitch with a short repeat that one could easily knit without looking or counting while at a math talk; no brioche or fancy stuff
  4. Preferably the knitting procedure would be the same on the right side and the wrong side, to avoid confusion/mistakes if knitting while multitasking
  5. Weaving in ends is tedious, so minimize the need for this
  6. Finished piece should lie flat and not curl up

Of course the first thing we tried was finding such a stitch in the existing literature; no need to remake the wheel if there are already perfectly good wheels! However, in this case our literature search came up short, so we wondered… could we construct a suitable stitch pattern by deducing certain things from our list of desired conditions?

Somehow we did; here’s how the deduction process panned out:

  • One way to satisfy the multiple-colors-one-at-a-time condition (2) is to use slipped stitches. We decided to riff off the slipped-stitches trick for knitting vertical stripes in the round, with each color traveling across the knitting one at a time, slipping stitches to skip over stitches in the opposite color. But in our case we wanted to have a reversible fabric, and to knit on straight needles.
  • A really easy way to satisfy the reversibility condition (1) is to use some kind of rib stitch. That would also have the added benefit of satisfying our lay-flat condition (6). We didn’t want something too stretchy so 1×1 rib seemed like a good idea.
  • Conditions (3) and (4) basically mean that we have to keep it simple, so we started thinking about the simplest possible way to have a 1×1 rib that slips over other colors. After a bunch of dead ends the most obvious thing ended up working: basically, doing 1×1 rib and then slipping twice to leave a gap for a piece of 1×1 rib in another color.
  • The key that made the whole thing come together was using three colors instead of two. With two colors on straight needles, you’d have to knit across and back each row to get back to the other strand of working yarn. But with three colors and straight needles, the parity works out perfectly: knit across with Color A and leave it there, then pick up Color B and knit back on the wrong side, then pick up Color C and knit across, and then pick up Color A from where you left it and bring it back along the wrong side.
  • The three-color method above also satisfies condition (5) because there is no need for weaving in ends every time you change colors; all the colors just travel up the sides of the work with no ends.
  • When you slip stitches, the carried yarn has to go somewhere. If it goes in front of a knit stitch or if its color peeks through another color, then your work is not going to look good. The final piece of the puzzle was to figure out how to slip stitches so that the carried yarn was hidden inside the work. We’ll show a picture of the method that ended up working after we describe the stitch.

Triple Check Stitch

Here’s the simple, reversible, three-color “Triple Check” stitch that resulted from our deductions:

  • In Color A, loosely CO a multiple of 4.
  • Pick up Color B and [K1, P1, s1wyib, s1wyif] to end of row.
  • Repeat: Pick up Color C and do the same four-stitch pattern for one row. Then pick up Color A and do it again. Then Color B. Then Color C, and so on.


All slipped stitches should be purlwise, whether the yarn is held in back (wyib) or in front (wyif); see the video Slip stitches wyib vs wyif for a demonstration.

Note that in each color we are only traveling along the knitting one time, in one direction; not going across the knitting and back again. At the end of the row just drop the color you are using and pick up the next color, which will be waiting for you.

Hiding the slips

So where is the carried yarn hiding under the slipped stitches? In the close-up image below we’re just done the s1wyif step, slipping a black stitch with the white yarn held in the front:


What happens next is that the white “yarn in front” strand needs to be wrapped over the black slipped stitch to the back of the work. Here’s the exciting part: When we wrap the white yarn over the black stitch, the carried yarn will make a white bump that lies exactly over an existing white bump from a previous perl stitch!

Every slipped stitch in the Triple Check pattern wraps over a bump of the same color in this way, either in front or in back of the work. The carried yarn under the slipped stitches is basically copying the “knit, purl” stitch of the 1×1 rib below it (which is luckily of the same color as the carried yarn), but without making any actual stitches. This color-matching on the slipped stitches is the secret sauce of the Triple Check pattern, since all of the slipped stitches end up invisible inside the work.

Triple W Stitch

The Triple W variant below is actually the stitch we discovered first (originally we called it “The W”), but it makes more sense as a variant of the Triple Check. The stitch pattern is pretty much the same as for Triple Check but twice as wide, with pieces of 2×2 rib followed by four slipped stitches.

  • In Color A, loosely CO a multiple of 8.
  • Pick up Color B and [K1, P1, K1, P1, s1wyib, s1wyif, s1wyib, s1wyif] to end of row.
  • Repeat: Pick up Color C and do the same eight-stitch pattern for one row. Then pick up Color A and do it again. Then Color B. Then Color C, and so on.


Triple Check and Triple W are good stitches for stash-busting projects that use up your random yarn scraps and leftovers, because you can change colors gradually as you knit. For a gradient/morphing look, change just one of the three colors at a time, leaving two of the colors alone for a while before changing again. Here’s a Triple W scarf-in-progress with a color-morphing rainbow look:


Again, if you’ve seen the Triple Check or the Triple W stitches before, then please let me know! These stitches are so simple that I feel like they have to exist somewhere, but I haven’t been able to find them. Or, maybe we found a piece of low-hanging fruit that everyone else somehow missed, stumbling on that rare combination of easy, interesting, and new? In any case, happy multicolor reversible multitask-knitting :)



  • Triple Check is now a project on Ravelry.
  • Holly (@antimonia on Twitter) found something by Nancy Marchant that looks just like Triple Check on one side. It’s brioche so much more difficult, and not identically reversible, but the front side matches perfectly!
    Screen Shot 2017-12-21 at 5.30.45 PM
  • Another good catch from Holly: You can get a reversible “tiny hearts” stitch by knitting two strands in white and one in red. After a couple of rows I started knitting/perling into the backs of the loops of the red stitches, to make them come to a sharp point and look more like hearts:
  • Trammell Hudson and Rod Bogart did some bind-off experiments and found that K1,P1 is a good bind off for the Triple Check:
  • More samples from Jacqueline Jensen-Vallin and Rod Bogart‘s wife. Love all the different color looks!
    Screen Shot 2018-01-28 at 12.31.29 PM



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Design Exploration with Vectary

Also published at Shapeways Magazine

Today’s 3D printing advice: Figure out what your design software is good at doing and THEN design something, not the other way around.

If you start the design process with a rigid idea of what you want to make, then you’ll have to bang your head against the wall to try to get your software to do what you need it to.  But if you have the luxury of being flexible about what you’re designing, then you can start by sitting down and making friends with some design software, and figuring out what it wants to make. Learn how to drive it, what it’s good at, what it can do that your other software programs can’t, and then see how you can push it to its limits. If you can be open about what you’re going to design, then you have the freedom to let your available modeling software guide the design process.

In a way it’s like making dinner; if you choose a specific thing to make then you’ll have a lot of work to do choosing a recipe, going shopping, maybe even finding specific cookware or learning new techniques, etc. But if you can be flexible then all you have to do is open your fridge and start thinking about what you can put together from the ingredients you already have.

Vectary is perfect for this process: It’s flexible, it can do things you might not expect, and it’s easy to experiment with. We just have to figure out what things Vectary likes to do. Let’s explore…

Getting Started with Vectary

So what kinds of things can you make with Vectary? Here’s a very introductory video showing some simple designs:

From this short video we can already see that Vectary has tools for:

  • Creating low-poly models;
  • Polyhedral designs and patterns;
  • Taking the wireframe of a model; and
  • Remeshing surfaces to make them smooth and organic-looking.


We don’t know how to do those things from watching this video, but now we have an idea of some possibilities.

To get started, go to the Vectary site and sign up for an account. Vectary runs entirely in your browser, so there’s nothing to download to your computer. Once you’ve signed in, navigate to your Dashboard and click the “Start Creating” button on a new project. Experiment with the different design tools and see what you can do, then check out the videos and articles below for more guidance and ideas.

Printing from Vectary

One particularly cool feature of Vectary is that it has a Shapeways plugin that allows you to check printability and cost in any Shapeways material, right from the design interface. This cuts down design time significantly, cutting out the steps of repeated exporting, uploading, and testing final revisions of your model. This quick Vectary video Create a 3D printed necklace pendant with Shapeways plugin shows how the process works:

For a more detailed walkthrough of the design process shown in the video, see B. Davids’ Shapeways article VECTARY Tutorial 1: How to Make a Necklace Pendant.

Notice that the video above gives us some additional insight into what design techniques Vectary handles particularly well; in the case of this model those techniques include:

  • Rotating a shape around an axis;
  • Pushing/pulling faces of a low-poly design; and
  • Randomizing patterned features.


To activate the Shapeways plugin shown in the video, you have to add it to your Vectary account. Check out the blog post Creating real objects just got easier: VECTARY integrated Shapeways for more information on how to do that.

There’s a catch, but it’s not too bad: To get commercial rights to the models you create in Vectary, you need to “pay with a share,” that is, you need to share your Vectary design on social media. Once you’ve done that, you can sell your Vectary designs as prints or on a service like Shapeways. This is an interesting balance between free and paid software; but for now at least it is nice to have a free way to use such powerful and interesting design software.

Teach Yourself Vectary with Tutorial Videos

To dive deeper into what Vectary can do, take yourself to school by continuing through B. Davids’ very well-done series of articles and videos on Shapeways Magazine. For example, check out the design walkthrough VECTARY Tutorial 2: Make a New Body for an RC Car, and the accompanying VECTARY video Redesign a toy car with Shapeways plugin:

The fun project outlined in the video makes a new chassis for an existing toy car. And, we get some more clues about the long list of design techniques that   knows how to do, including:

  • Sketching and extruding 2D designs from measurements;
  • Selecting, transforming, and moving points, lines, and faces of your design;
  • Joining nearby points to create a closed mesh;
  • Mirroring part of an object for symmetry;
  • Beveling faces and creating holes in a surface; and
  • Adding thickness or offset to your design for stability.


You may or may not not want to make a toy car chassis, but these techniques can be applied to many other types of projects.

Next up is the design walkthrough VECTARY Tutorial 3: Create a Minimalist 3D Printed Cactus, with accompanying video Create a twirly cactus with VECTARY:

This video will give you more practice with low-poly modeling and rotational patterns. In addition, we can add these techniques to our growing list of “what’s in Vectary’s fridge”:

  • Rotating groups of selected faces;
  • Loop-selecting edges for beveling, offsetting, and smoothing; and
  • Modifying a template to create variations of a design.


Finally, try experimenting while reading the walkthrough Vectary Tutorial 4: Create a Halloween Unicorn Maskand watching the accompanying video Create a Halloween Unicorn Mask with Vectary:

This final B. Davids tutorial video added a couple more items to our what-Vectary-likes-to-do list:

  • Scaling portions of a design with certain symmetries;
  • Creating patterns of new faces to create finer features; and
  • Using Boolean operations like “subtract” with the help of a plugin.

Going Further

From these videos we’re starting to get a good idea of the kind of modeling that Vectary is best at: low-poly modeling followed by smoothing in the final stages. The Vectary design process involves sketching, transforming, and moving faces, edges, and vertices; then pushing, pulling, patterning, and beveling to sculpt a rough object; then “baking” into a smoothed object for a final, more organic-looking design.

If you’re not ready to come back from Vectary school yet, check out the Vectary YouTube channel for tons of design videos. Two of my favorites are the polyhedron-flavored How to create a cubic ring with Vectary

…and the polygon-flavored How to create a geometry bracelet with Vectary:

I’ve played around with a lot of design software, and Vectary is one of the most interesting and promising ones I’ve seen in a while. It’s simple and intuitive, but gives you access to powerful low-poly modeling tools that are usually only found in more complicated or expensive software packages. If you create something with Vectary, let us know so we can feature it in a future post!



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