Half square triangles are another important subunit in making quilt blocks and quilts. A half square triangle block is a square made of two different fabrics, so that each fabric forms half the square joining along the diagonal.
This instructable shows how to construct a half square triangle block from 2 squares of fabric so that they are ready to be used in a quilt. Calculating the correct size of starting square to end up with the desired finished size is also discussed. After following this instructable a student should be able to construct half square triangle units as used in many traditional quilt blocks.
Step 1: Materials
washable fabric marking pen or pencil
or needle and thread if you hand piece (i.e. no sewing machine)
Rotary cutter (not absolutely necessary, but makes cutting squares much faster)
My sewing instructions will all be for machine piecing, but the basic idea, cutting, pressing and layout are the same for hand piecing.