Dottore has many clones to assist him in his work, and you can barely tell them apart (except from the super obvious ones). Sometimes you figure out which segment is which by their physical build, the older ones tend to have broader shoulders compared to the younger ones. Theta (older) and Omega (younger) look very much alike, same mask design and all, only thing that differentiates them is their overall build, and their personalities differ; Theta is warm but Omega is rather snappy.
One time you wanted to ask a segment about dinner choices, but you didn't want a fight... the only segment you see in your line of sight was either Theta or Omega.
So you grab a measuring tape, approach him, and measure his shoulders to find out which one he is, it turned out to be Theta, so you struck up the conversation.
you can say Theta was very visibly puzzled.
"(name)... Why did you just measure my shoulders?"
"To... differentiate you and Omega?"
"You pay attention to our... measurements?"
"Yes...?"
"You're much more of a creep than I thought."