> For the complete documentation index, see [llms.txt](https://help.prequilt.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://help.prequilt.com/prequilt-101/build-a-block-unit-for-the-fabric-calculator/triangular-units/triangle-in-a-square-tri-rec.md). # Triangle in a Square (Tri Rec) Best Practices for Auto Recognition

Triangle in a Square Block Unit

## Triangle in a Square (Tri Rec) Block Unit in PreQuilt This more intermediate or advanced block unit can be tough to nail in the sewing room. But it's pretty easy peasy in PreQuilt. **Triangle in a Square** block units are constructed using one isosceles triangle with a half rectangle triangle on either side of it. Overall, these three shapes within the overall square shape. This shape is also sometimes referred to as a **Tri Rec** (and if you know why, please let me know!). And since the idea behind this series is to build a block unit that can be used to create a larger block, I'm going to create a 12" finished block that has Triangle in a Square block units in it (like for example, the **Sun Rays** quilt block). *** ### YouTube Video *Coming soon...* *** ### Help Guide 1. Click on the **BLOCKS tab** on the left side control panel.
2. Click on the **Make Custom Block** button.
3. The **Block Editor panel** will slide out and overtake your screen. My block is set to 12" x 12" finished, but it doesn't matter, the next steps will work for all sized blocks. 4. Set your grid guidelines by changing the number for the horizontal and vertical units. * Since I'm going to be creating the **Sun Rays** quilt block, I'll set my gridlines to 6 horizontal and 6 vertical units.
5. Click on the **half square triangle shape** () from the central control panel. 6. One half square triangle will be added to the block space. **Move** it into the correct position by clicking on the shape on the block space and moving it to where it belongs.

HST shape added to the quilt block space

HST shape moved to build the block

7. We now need to stretch the HST so that it's rectangular. **Grab** the square on the top side of the HST and **drag** it until the triangle fills the height of only 2 vertical grid spaces. * Note: If the snap to grid is turned on (default) then the shape will automatically fill the grid space.
8. Click on the **half square triangle shape** () from the central control panel.
9. Click on the **Rotate button** (![](https://667278489-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FPUFswdysHBJDPIJC9xe0%2Fuploads%2FGR6TNyrDdrPEBMQ1kC2G%2FRotate.png?alt=media\&token=dee9dfad-4200-4439-9f46-abdcffb41cdf)) on the central control panel so that the half square triangle is oriented in the opposite direction as the first one was. * Note: You will need to click on the rotate button a few times to get it in the right orientation.
10. **Repeat** Steps 6-7, but make sure to create a mirror version of the first half rectangle triangle.
11. Click on the **isosceles triangle** () from the central control panel.
12. Click on the **Link button** for a different fabric link (so that there are 2 different fabrics being used in your half square triangle block (unit). In this example, I'm linking to Fabric Link C.
13. Click on the **Rotate button** (![](https://667278489-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FPUFswdysHBJDPIJC9xe0%2Fuploads%2FGR6TNyrDdrPEBMQ1kC2G%2FRotate.png?alt=media\&token=dee9dfad-4200-4439-9f46-abdcffb41cdf)) on the central control panel so that it is in the correct orientation.
14. **Move** and **drag** the new triangle piece so it fills the empty space of the triangle in a square block unit. It should snap into place and be snug between the 2 half rectangle triangles.

1 x Triangle in a Square block unit

15. **Create** the remaining block units to complete the Sun Rays quilt block.

1 x Triangle in a Square block unit

Sun Rays Block with 4 Triangle in a Square block units

*** ## Sewing Construction Diagrams ### 1 at a Time Method This subcut method has left over fabric. Add another Fabric A square to make another identical block unit.
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