While the end product is obviously precious and a work to be proud of I hope you realize you are walking a very thin line. I quote wikipedia.
Self-plagiarism (also known as "recycling fraud" is the reuse of significant, identical, or nearly identical portions of one’s own work without acknowledging that one is doing so or without citing the original work
Since you are acknowledging the original work you may be ok in this regard.
I would be careful to not mix up the shirts though as this might constitute
failure to cite the original.


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“You live and you learn, but if you never learn, at least you are still living.”
— Unknown
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