Space Cadet Block 3 and a Quarter Square Triangle Tutorial

Today’s star block is commonly known as Variable Star.

In the slots in which Space Cadet block 2 contained Flying Geese segments, it sports quarter square triangles (QSTs).

Let’s sew those first:

Making the Quarter Square Triangles

The general measurement rule for making quarter square triangles is to add 1.25″ to the size of the finished QST size you want to make.

So for our block today we need to make 4 3″ QST segments. Therefore we need to cut 3″ + 1 1/4″ = 4 1/4″ squares from our background fabric and star fabric.

1. Cut 2  4 1/4″ squares of each fabric.

2. Draw a diagonal line across the back of your (lighter) star fabric squares.

3. Put one marked square on top of each (darker) background square, right sides facing.

4. Sew one seam 1/4″ to the right of the marked diagonal line and one 1/4″ seam to the left of the line. The photo shows the front and the back side.

5. Cut between the seams. Press the units open and trim the v-shaped dog ears. At this point you have made 4 half square triangle units.

Have a look and compare these with the HSTs of Space Cadet block 1. We are half way to the QSTs! 

6. On the backside of two of the HST units draw another diagonal line like you did in step 2. This line will cross the seam you just sewed.

I hope you can see the drawn lines at least a little.

7. You probably guessed it – sew again 1/4″ to the right and to the left of that diagonal line.

8. And yes, again cut between the seams.

9. Press open your brand new quarter square triangles and trim the units to measure 31/2″ square.

Finishing the Star Block

10. From your star fabric cut one 3 1/2″ square. From your background fabric cut 4 3 1/2″ squares. Lay out your star block using the squares and your QST units.

11. Sew each horizontal row of squares and QSTs. Press the seam allowances towards the solid squares.

12. Sew the rows together to finish your star block!