This one looks like a 16 patch, (4x4) with the 4 center boxes replaced by one larger
For a 12" block:
That makes each square 3 - 1/2" (3" finished, 3x4=12)
for half square triangles, I'd cut matching squares an inch bigger (4-1/2"), mark diagonal, sew 1/4" on both sides and cut down the middle. That gives a bit of wiggle room to trim perfectly.
The paper piecers can point you to dog patterns. If you look at quilterscache.com, you can browse through and get a name for the main block. If you save pictures from the internet, you can rename them to the block name or referring site to make easier to find again.
In general, if you see a pattern online, the person that posted has easy access to the information.