With t-shirts there's always a problem of fit - not enough S-sized, too much XL, or vice versa. Someone prefers baggy tee, some are after a spot fit, some go polo. Men and women sizes and styles also are different. So I thought, why don't we try long tees, kind of those ones you see on youth music bands. Such t-shirts look good both baggy and tailored on both girls and boys.
I did multiple iterations on design and came up with something very basic and meaningful like this: