K---A1 is all HSTs with the 4 corners being blocks that you add a triangle to one corner. I haven't done the math but if you want to do it with HSTs I could redraft so you could cut HSTs with a small template if you like. The corners could be done by cutting a small square and sewing it onto the larger square and trimming . \
If you like I could work it up for you and you could see which you would rather do template cutting or paper piecing.
I don't paper piece so templates are always my choice. I can provide the small template free. Just let me know.
Here is a link that was posted earlier by Butterflywing
There is a list of blocks you can see up close.
http://members.tripod.com/~Lisa_Jane/rowa.html