Pattern Matching Quarter Square Triangles


Before we get into details, let’s start by defining a few terms. Fussy cutting or meticulous cutting is a catch-all term for being intentional about how you’re cutting the fabric instead of simply putting your ruler down and what you cut is what you get. There are two general and overlapping categories of fussy cutting: motif highlighting and pattern matching.

Motif Highlighting is what happens when you want a particular part of the fabric featured in a specific part of your quilt or block. The block below is an example of motif highlighting. The cameo is centered in the block, pulling focus to the face.

Pattern matching is cutting the fabric and sewing it back together in such a way that reassembles the image you just cut apart. Usually, pattern matching includes motif highlighting (because why else would you bother?), but sometimes the purpose of pattern matching is achieve a kaleidoscope effect rather than recreating the image. The block on the left is an example of pattern matching to achieve a kaleidoscope effect. The block on the right is an example of pattern matching to recreate an image. There are four seams coming together to recreate the trash panda’s (raccoon’s?) face.

First – Gather Your tools

Having the right tools will make this whole process easier. I used starch, hot iron, rotary cutter, a good ruler, and a water soluble glue stick. Maybe a marking tool if your ruler isn’t the just right size for what you’re making. And my sewing machine…does that need to be included or can we just assume? Anyone doing this by hand?

A Quick Break for Math

We are pattern matching quarter square triangles. YOU CANNOT MAKE THOSE TWO AT A TIME. Therefore, with most patterns a math adjustment is required. Pattern writers will often have you use a 2, 4, or 8 at a time method because it goes faster and uses less fabric. When you make half or quarter square triangles one at time the size squares you cut are the sizes you finish with because you are sewing on the diagonal (instead of a 1/4 inch on either side if it). So if you cut two 4.5 inch squares and sew down the diagonal, you have a 4.5 inch square again after you trim and press. Since we’re going to have to sew two seams to get from squares to quarter square triangles, I’m going to add a half inch to give myself some room to trim and square the block when I’m done. Since I want to finish with a 4.5 inch block, I’m going to cut 5 inch squares to give me some wiggle room to make mistakes. Because the great philosopher, Big Bird, says, “Everyone makes mistakes, so why can’t you?”

Pick Your Motif

To make a quarter square triangle block to pattern match, you must have 4 full repeats of the motif in the size you need to cut. For me that, that’s four repeats of the motif that are 5 inches square. This is the part of the process where a ruler made for fussy cutting is a lot of help. I have Marti Michelle’s and one by Riley Blake. What makes these helpful is the x in the middle that let’s you center your block and see where the seams will be. You can see an examples of both rulers over the fabric below. The Marti Michelle ruler (right) has guides for a 1, 2, 3, 4, and 6 inch block, so it’s a lot more versatile than the one on the left. But the one on the left happens to be the perfect size for this project.


This is one of the MOST crucial steps in the process: starch. So much starch. Fabric is floppy and wiggly and shifty. You cannot trust it to stay put, and we have a lot of little lines to match up here. I use Mary Ellen’s Best Press, and I like it a lot. I spray a generous amount of starch to the back and then flip is over to press. A nice hot iron is key here. You should see some steam rising from the fabric. That is the starch setting. I will often apply another round of starch and press again. You want your fabric to have the feel of thin cardstock. You can see below that I pinched the top of both blocks. The block on the left has not been starched. Look at all the movement. The one on the right is nice and still. Once you have your fabric nice and starched, you can start cutting.

Cutting Your Block

I’ve starched my fabric into the stiffness of a Victorian Aristocrat, so now it’s time to make some cuts. Remember how I said I was adding a .5 inch to the finished block to give myself some wiggle room? This means I have to do some marking before I cut because I don’t have a pretty 5 inch ruler. So I set my 4.5 inch ruler over my fabric and line it up over the part of the motif I wanted centered on the finished block. Then I mark four reference point. Next, I use a different ruler to cut a 5 inch square. I get that’s not pretty/fancy, but I cannot afford to buy a new ruler for each project. Which means, there’s often some creativity/flexibility happening.

Now I have one pretty 5 inch block, but I need three more. So next I take the block I just cut and line it up on top of the next fabric I want to cut. This next fabric I’m cutting has already been starched. Did I mention how important the starch is? Just checking. I’m trying to get as many points of the motif on the top fabric to match the bottom. After you place your reference fabric on top of the one your cutting, using your fingers to gently slide the top fabric so as much of the pattern matches as possible. IT WON’T BE PERFECT. Fabric moves and stretches as you press and cut. No one will ever look at it as closely as you are now. This is why starch is so important, but it still won’t be perfect. When it’s lined up as best as can be, make your cut.

Preparing to Sew

I can only get half and quarter square triangles to pattern match when I sew from the top left corner to the bottom right corner. I’m sure someone smarter than me can explain why that is. I’ve just accepted it as fact and don’t fuss with it. Also, this was the point in my tutorial making process where I noticed that my other two fabrics were not big enough to cut my motif at 5 inches. I’m going to have cheat the skull block and that doesn’t make a good example. Thus, with a bit of magic, we’re now making a bee block. Ta dah! What’s fun about the bee block is we only have three color variations, so we’ll also have to pay attention to color placement. We don’t want the two blue fabrics side by side.

Divide your four fabrics into pairs. If you have any fabric that is the same or similar, put them in separate groups. This separation prevents them from being next to each other in the final block.

Since I have two of the same colorways in each group, I need to make sure they don’t end up touching. So in group one, I’ll pick the blue as the top fabric and in group two, I’ll pick it as the bottom. Which ever fabric you’ve picked for your top, fold it in half, wrong sides together, and lay it on the fabric you’ve chosen for the bottom. This lets you see if you’ve folded the top fabric the correct way. Once you have the fold correct, take it back to your ironing board and press it along the diagonal.

I also like to do a quick check of how it’s going to look finished. Before sewing anything I fold one of the blocks a second time and put them all together to get a feel for the finished product. Feel free to rearrange your fabric until you like what you see. This part can feel it bit confusing. It takes some practice to fold the fabric in such a way that it matches. Give yourself some space to play and practice. It’s the only way to learn. It’s also helpful to take a pictures of your arrangement so you don’t get turned around on the last step.

Notice that none of image lines up well here. I’m only trying to get an idea of what colors will end up where in the final block.

Here’s where we get to the actual pattern matching. Take the triangle you’ve made by pressing the square along the diagonal and put some water soluble glue on the side that will become the seam allowance (check out the picture if this seems confusing). Place the piece with the glue on top of your bottom square. Using the same process as you did when you cut, slide the top fabric until it matches the bottom as best it can. I learned about glue basing from Bobbi who you can find on Instagram @geekybobbin or you can check out her blog here.

Repeat the process of pressing the top fabric in your second group along the diagonal and gluing.

Time For Sewing

There are some masters of sewing who can fold back their top block, sew right on the fold, and get a delightfully matched block each time. I am not that master. So I need extra help. To do that I picked a sewing foot that shows me right where my needle is going to hit. Then, I set my machine to it’s biggest stich and baste the pieces together. Why yes, that’s right, I baste with glue AND thread when I’m pattern matching half and quarter square triangles. Sewing on the bias is tricky and some patterns have more lines to match than others. Using a basting stich first makes the need to rip and redo feel like a normal part of my process rather than a failure. (Remember what Big Bird said?) I learned about using a basting stitch from Lou who is on Instagram as @sand_salt_sew

If things line up, I do happy dance and move on. If they don’t, I scowl at no one and try again. This is also when I remind myself that finished is better than perfect. I’m not making a show quilt, and likely no one will every look this closely at the block ever again. Sometimes I need to look at it from a distance to reassure myself that the match is enough. If I’m keeping it, it reset my stitch length and sew over the basted line. Then I repeat the sewing processing with the second block. For this block, I didn’t like my first attempt, so I redid it. You can see both blocks

When I have two block sewn together that I am satisfied with, I check a zillon times to make sure it’s right and then trim off the excess and press the block open. BE GENTLE WHEN YOU PRESS. The starch reduces the amount of shifting, but you’re still on the bias and have one seam to go.

Don’t forget to double check you’re cutting on the correct side.

Time to repeat: fold, press, glue baste, thread baste, check, sew the seam, check x 100 and trim. When I reach the glue basting step, I check to make sure my seams are nesting and that the pattern matches in the center where the seams are nesting together. You can see on the block below I did not check and the center is a bit off. Being a bit off isn’t the end of the world, and I like to try my best where I can.

Look at the center of the block. See how the seams don’t match, but the pattern does? Also, look at how wonky the edges are. This why I add that extra .5 inch for trim space.

I didn’t take as many pictures of this step when I was making the bee, so I took some when I went back and finished the skull block. Here they are:

You did it! Congratulations! If yours is anything like mine, the edges are a little wonky. Time to square it up. Here is where I love my little 4.5 ruler because is has pretty lines I can use to keep my motif centered. If you don’t have that, you can use the diagonal line on any square ruler and use whatever half of your block is (in this case 2.25 inches) as a center line. Then trim to 4.5 inches.

TA-DAH! You did it! Great job!

PS I’ve been actively practicing my pattern matching skills for about five years now. If this is your first time, give yourself permission to be a beginner. This is advanced sewing. Also, these techniques cannot be applied to sewing together rectangles and squares without making some adjustments. When you sew triangles, you want two squares that are exactly the same because you’re sewing on the diagonal. When you’re sewing straight pieces together, you need to adjust what you consider seam allowance to allow the patterns to match correctly. I made tutorial for that years ago…you can see my growth because I didn’t even start by having you starch your fabric. Rookie move.

PPS I hate the waste that comes from sewing half and quarter square triangles one at a time so I sew together the bits I trim off. Sometimes my seams are so good I end up with two bonus 4.5 inch blocks and a 3.5 inch block. On this block my seams were wonky so I ended up with two 4 inch blocks and 3 inch block. Happy Sewing!

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