They wanted to run forever

Ten and his companions I know there are already ponyfied versions of them, but I wanted to make my own. My favorite is Rose Tyler  
Question: What are their cutie marks and what's the reason behind it? Possible spoilers!

Rose Tyler: I chose a wolf and roses for her, pretty simple, with Rose as the companion in the Show you often (especially in season 1) get to hear or see the words "Bad Wolf", that has a special meaning. I don't wanna spoil the season 1 finale though, I'm just gonna say it stands for "Bad Wolf", and the roses are obvious I hope.

Martha Jones: It didn't work with the Doctor as she wanted it to, so later she starts working at UNIT, you can see that when the Doctor and Donna meet her again, and her CM is the logo of UNIT.

Donna Noble: Her CM is the Time Beetle, the one that sits on her back in an episode and changed time. It was pretty special because it showed how important Donna was and how the Doctor couldn't  make it without her.
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