I really love the TLMOE costume department for so many reasons, but one of them is this: Tandy’s t-shirts occasionally hint at the plot/resolution of the episode! (this is something I’ve completely failed so far to successfully gif, so you get this long post instead.)
Tandy’s shirt in The Open-Ended Nature of Unwitnessed Death is a messenger pigeon, and the episode’s all about trying to leave a message to someone.
Tandy’s shirt in The Spirit of St Lewis (the episode where Lewis dies) is birds flying out of a cage. Doves are sometimes released at funerals to symbolize the soul of the deceased being released. (I hate TSOSL, but I love that detail)
Then at the end of that episode Tandy’s wearing a sunset, because (what with Lewis being dead, Gail presumed dead and Melissa locked up) it’s arguably the group’s darkest hour. Except that you could also see it as a sunrise, meaning the opposite, and of course right before the credits Gail turns out to be Not Quite Dead.
Back to the sun again! In the series 3 finale, where everyone pours over maps to find a place to go and eventually decide to try Mexico, Tandy’s wearing a map marker with the sun inside it.
And finally, in the ending scene of Double Cheeseburger, where Tandy’s holding baby Mike, he’s wearing a t-shirt with planets on it. You can’t see it properly in the show, but it’s this one, the aptly named “You Are My Universe” tee –
An astronaut giving a gift to a girl.