If you are interested, here is a [link] to the page in my sketchbook that has the development of this design. It should give a hint about how long it takes to make something like this. If you want to see the sketches of some of my other designs, I would be happy to share
[link] here is the translation
ok... but if I do that, and it covers 10% of the design (as an aside, it will be obscured by other parts of the design, so it may take up 5% at most, if we count the whole area of the circles instead of just the lines.) then you will make o.33 cents per T-shirt, so 1/3 of a cent. At that rate, I will need to sell 660 shirts before you would see $20 dollars. I'm not exactly a corporation or anything, I expect to sell maybe 20 of these shirts at most, I am only making the design because a friend requested it.
while I was waiting for your reply, I did take a crack at making these things myself. didn't finish it yet, and it's not as nice as yours.
I'd have to think about it.