This is just one of the blocks you can do with 16 half square triangles (HST) but the possibilities are endless.

For this tutorial I start with 5 inch squares, which gives you 2 inch HSTs, but you can start with any size square.

You will need to trim the resulting HST to size afterwards.

Here is a 2 minute video showing you how to make 8 HST at once:

Example blocks with 8 HST

Example blocks with 16 HST in 3 colours

There are many more blocks you can do with HSTs. A quick Google search will confirm that.