NG - Seams Possible

T-shirt Embellishment with Paint Sticks 
You can also do this on a T shirt.  A flat piece of cardboard under the t-shirt would be helpful.

For the picture shown, I used a fine point permanent marker on the light fabric, but the dark fabric makes more of a stark contrast.

I do have some pieces of Black fabric I will bring with me.  Jeans fabric will work as well.