You probably need 4 blocks to show the secondary block. Most of what I can think of would be stars for both the primary and secondary block. Here's one example:
http://quilterscache.com/L/LuckyStar2Block.html
The star is the block, but if you look at the corners of the block, you will see a half square triangle. This produces a pinwheel secondary block when put together.
You can look for more at
http://quilterscache.com/QuiltBlocksGalore.html