Not sure what you are asking, but the only way to avoid a Y seam is to add an additional seam, usually in the center piece of the 3.
Here's an example. In the lemoyne star block, you normally have y seams for the background patches (left half of star). if you add an additional seam (right side of star) you can just seam it normally.
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If you have already cut the fabrics, you won't have enough to do this because you have to cut those pieces larger to allow for an additional seam. If you haven't cut them, then you could do this. I would for sure do a practice block with scrap fabric first.
(sorry for additional star image... can't get rid of it).
Last edited by PaperPrincess; 02-15-2017 at 05:22 AM.