This person has fairly short hair, and there seems to be some sort of mechanical device attached to her ear. She's wearing a long-sleeved shirt, a pair of white shorts, and a translucent, plastic skirt. And... She seems to be flickering.
She's sitting, unmoving, on a chair in the corner of "room". You think she looks strange, and a bit frightening.
"Hello?" Heart says.
This person nervously looks away from you. Heart pulls up a chair from a stack of chairs in the corner, placing it next to her, and sitting down. You do the same.
"Hello..." The person says quietly. 
"I'm Heart." Heart says.
"Diamond." You say, gesturing to yourself.
"What's your name?" Heart asks the person.
"Triangle." She says.
"Triangle! Lovely." Heart says. 
You're unsure whether she's actually making an effort to be kind to Triangle, or if she's just trying to get this over and done with.
"So, uh, what's up with the flickering?" Heart asks her.
"I'm, oh, how would you put this..." Triangle mutters, "I'm not human. I'm a hologram. I'm supposed to be a guide for people who visit Static Mosaic."
"So that's what this place is called..." You say, "Right, Triangle?"
She nods.
"I'm not a very good guide, though, so I spend most of my time in our break room." Triangle explains, "We haven't had many visitors in recent years, anyway, so I was surprised to see you two."
"Well, we need your help." Heart says.
"What do you need?" Triangle asks excitedly. You can see a faint glimmer in her flickering eyes.
"Well, we've lost our friend Star, and all we know is that she's in here somewhere." Heart explains.
"I see." Triangle says, "Well, this is the one time when having barely any visitors is a good thing. I believe she passed through here a few minutes ago. I can sense her in a room nearby."
"Could you please lead us to her?" Heart asks.
"Of course!" Triangle says, "Please, follow me."