Half-square triangles
Birds in the Air
A flock of half-square triangles all pointing the same way, with open sky in the upper-right corner. Piece six identical HST units and three plain background squares, then sew into three rows so the feature triangles march along the diagonal.
Cut list
Dimensions for a 12 inch finished block with a standard 1/4 inch seam allowance. Scale proportionally for other finished sizes.
| Region | Role | Pieces | Cut size |
|---|---|---|---|
| Bird Top Left | Feature | 1 | 4 7/8" × 4 7/8" |
| Sky Top Left | Background | 1 | 4 7/8" × 4 7/8" |
| Bird Mid Left | Feature | 1 | 4 7/8" × 4 7/8" |
| Sky Mid Left | Background | 1 | 4 7/8" × 4 7/8" |
| Bird Bottom Left | Feature | 1 | 4 7/8" × 4 7/8" |
| Sky Bottom Left | Background | 1 | 4 7/8" × 4 7/8" |
| Bird Center | Feature | 1 | 4 7/8" × 4 7/8" |
| Sky Center | Background | 1 | 4 7/8" × 4 7/8" |
| Bird Bottom Center | Feature | 1 | 4 7/8" × 4 7/8" |
| Sky Bottom Center | Background | 1 | 4 7/8" × 4 7/8" |
| Bird Bottom Right | Feature | 1 | 4 7/8" × 4 7/8" |
| Sky Bottom Right | Background | 1 | 4 7/8" × 4 7/8" |
| Sky Top Center | Background | 1 | 4 1/2" × 4 1/2" |
| Sky Top Right | Background | 1 | 4 1/2" × 4 1/2" |
| Sky Mid Right | Background | 1 | 4 1/2" × 4 1/2" |
How it goes together
- Step 1
Cut your pieces
Cut each region using the dimensions in the cut table for a 12 inch finished Birds in the Air block. Standard 1/4 inch seam allowance is included.
- Step 2
Sew sub-units
Sew the smallest units first (half-square triangles, flying geese, four-patches), then build outward.
- Step 3
Assemble the block
Join the sub-units into rows or columns, then join the rows. Press as you go. Square the finished block to size.
Read more
Color value vs hue in quilts
Value is how light or dark a color is. Hue is what we usually call “the color itself.” In quilts, value carries the design — hue carries the mood.
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Quilt block families, explained
Most quilt blocks belong to one of six families — Patchwork, Half-square triangles, Flying geese, Stars, Curves, and Hexagons. Each family is a way of piecing fabric together.
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The quilter’s seam allowance, explained
A seam allowance is the strip of fabric between the seam and the raw edge. Quilters work in a standard 1/4 inch — and getting it right is the difference between a top that finishes flat and one that fights you.
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Try the Birds in the Air on a real layout.
Open it on the Design Wall. Try a few colors, see the math, change your mind.