A common patchwork unit where getting a good line up can be tricky is the “Square-in-a-Square” unit.

Four triangles are sewn around a central square.

It should finish as shown in the photo above, with enough of the triangle fabric remaining all round to leave a quarter inch seam allowance beyond the points of the central square.

Then the point will look perfect when the next piece is stitched on.

Lining up pieces for Square in a Square

When you follow a pattern for this unit, as soon as you try to stitch the first triangle onto the square, you will notice that the two pieces have edges of different lengths. This is correct, so don’t trim them down!

The secret for the Square in a Square is to line up the centre of the triangle edge with the centre of the edge of the square.

The easiest way to find the centre is to fold the long edge of the triangle in half, and pinch to make a small crease mark.

Fold the side of the square in half, and pinch too.

Now line up the crease mark of the triangle directly over the crease mark on the square.

You should have an equal amount of the triangle sticking out at both sides.

Pin and stitch.

Stitch a second triangle onto the opposite side of the square in the same way.

Then stitch on the other two triangles, again matching the centres. This photo shows how it will look when lined up correctly:

Lining up the third triangle 

Note how the stitching line again goes from the place where the edges of the two triangles cross over.

This should ensure that you get a perfect result as shown in the main picture above.

Using Square-in-a-Square blocks

Mrs Brown’s Choice

Quite a few blocks include this “Square in a Square” unit.

If you would like to try this out for yourself, there is a free download pattern for this 12″  Mrs Brown’s Choice block in the Shop.

This includes four Square-in-a-Square units, so you can practice them and become more confident. It’s quite an easy block, as there are no points to match.

This block can be done in any two colours, or in three as shown here.

Ribbon Star

Another block which uses a Square-in-a-Square unit is Ribbon Star.

Although it looks simpler, it is in fact a bit more advanced, as it includes Flying Geese units as well. If you would like to try this one too, you can buy the download pattern for this Ribbon Star block for £2 in the Shop.

It’s also more fiddly than you might expect to line up the points of the Flying Geese with the Square-in-a-Square units, but the pattern includes lots of tips to help you achieve this.

If you would like to do a complete project, my Friendship Star pattern available in the Shop has an “Air Castle” block on the quillow pocket – can you see the “square in a square” at the centre?

Air Castle is one of three different blocks included in the Friendship Star project.

If your Square in a Square doesn’t look correct (see photo to the right!), then you have probably lined up one end of the triangle onto the edge of the square by mistake. This leaves a huge “wing” at the other end, and will need unpicking and restitching – it’s never going to work…..

Although square in a square always needs the centres lining up, for other units it may sometimes, be correct to line up one end of different sized pieces – look at Why won’t it Fit….? Part 1 Flying Geese (in the Hints and Tips section) for an example.

If it doesn’t tell you in the instructions, how do you know how to line them up if they are not the same length? It comes with experience really, and by looking at the shape and measurements of your finished unit.

So, if you are not experienced enough yet to do this without help, find a good teacher!