It was clanking that awoke Sia. Clanking and muttered groans of frustration and more clanking and- Sia rolled over, lifting an arm to check her clock, red LED's glowing harsh. 8:13. Gem had had worse episodes. Sia strained her neck to check the corner of the room where Gem's scrap heap resided. It was less of a heap, now, more of a...mound? Pile? The words still seemed too big. Whatever, it was smaller than it had been when they'd gone to bed. Or at least, when Sia had gone to bed.
"Gem?" Sia said gently, sitting up in bed, carefully prodding her sister. It was important not to startle her in an episode. Who knew what she'd constructed. "What've you been building?"

Gem dropped the scrap that was in her hands and hovered a hand over a pile of odd, near-spherical objects that lay beside her. She picked one up and cradled it in both hands, standing and turning around - Sia could see her eyes were bloodshot, hair greasy and pulled back. Oil marked her face, though Sia couldn't see any cans or containers in the room. How did she always manage that?
"Bombs."
Oh. Good.
"At first explosive!"
Naturally.
"Just plain bada-boom, y'know, bit of gunpowder? But then I saw these," Gem threw her arm behind her and scooped up some metal shavings, "and I thought, what about a dispersal system? Like, a scatter-bomb." Sia nodded along, ignoring her need for coffee. It was best to let Gem talk. "And that got me thinking about dispersal systems in general! SO many different things you can put in a bomb, Si, it's crazy! This one's just the boom, but you've got EMP's, sonics, heat. You just put this there and then that goes around here and then you press this-"

Sia leaped frantically from her bed and nearly tackled Gem in sweeping the bomb from her hands, then fled to the window, flinging it open and tossing the small metal bomb out into the open air beyond. It clicked mid-flight and Sia pushed herself flat to the ground. There was a boom and a rumble and Sia got up, peeking out of the window. There was smoke, and a small piece of metal was vibrating in the wall next to their window, but through the lingering black plume Sia could see small bits of coloured paper fluttering gently in the breeze, starting their fall to the ground.

"Oh, that one was confetti. A celebration-bomb!" Gem said from behind her, cheerful and spacey.
"What were you celebrating?" Sia asked, exerting calm upon herself, turning around to face Gem.
"Well that's for whoever throws it to decide."
Sia tried to respond, but the tannoy crackled to life, and whatever she was about to say was cut off by the icy tones of their school's icy headmistress.
"Gemini and Siamese. Attend breakfast. And then my office."

Sia groaned, rooting through her drawers to find suitable clothing. Gem just grinned.
"Excellent." She said. "I'm starving."