i've been working on the last few of these arrow blocks and came across an idea that i wanted to share.
with these arrow blocks, the wings of the arrow are made from a single pair of hsts, cut from one block set. if you are only making one block from any given fabric, you just have to deal with what you have and accept that, if using a directional print, one of the wings won't be matching up with the center square. however, if you are doing two blocks (or an even number of any amount), you can adjust that.
when doing two blocks, you can switch around your hst units so that you can get them both going in the same direction. you will end up with the directional print going in different directions on each block, but the whole block will be uniform.
here's another example:
you can apply this logic to any block or pattern that uses hst units in pairs.