Mia rolled across the bed lazily before turning her head toward the study desk beside the window. Under the soft glow of the desk lamp, Rosalie was still awake.
Books were stacked around her in uneven piles, some opened halfway while others were filled with colorful tabs and handwritten notes. She continuously pulled out different references, scribbling equations across pages before flipping through thick theory books again. Several rough sketches of mechanical joints and arm structures were scattered across the desk.
Mia stretched lazily before climbing down from the upper bunk. As her feet touched the floor, she noticed Lily sleeping soundly on the lower bed, completely buried beneath her blanket.
Yawning softly, Mia shuffled toward the water cooler.
The dorm room was unusually quiet tonight. Outside the window, the campus lights flickered faintly beneath the dark sky while the late-night wind brushed gently against the curtains.
She filled a cup with cold water and took a long sip before glancing back at Rosalie, who remained fully absorbed in her calculations.
"Rosie… you're still awake?"
Mia asked sleepily.
"It's really late already, sweetheart."
She poured another cup and walked over, placing it beside Rosalie.
"Drink some water first. Cold water helps you stay refreshed."
Rosalie didn't even lift her head immediately. Her eyes remained fixed on the textbook as she reached for the cup and drank quietly.
Mia tilted her head, peaking at the pages filled with diagrams and matrices.
"The light bothering you? I can cover it a little."
"It's okay,"
Mia replied softly.
"I just woke up again. Why are you still awake?"
"I was lying down earlier, but I couldn't sleep properly,"
Rosalie admitted while leaning against the desk.
"Something still feels unfinished in my head."
Mia gave a small hum of understanding.
"Still,"
Mia continued, crossing her arms,
"if you keep doing this every night, your health is seriously going to suffer. Brother Julian literally told me to keep an eye on you, you know. He said you've been skipping sleep again."
A faint smile appeared on Rosalie's lips at the mention of Julian.
"You should sleep earlier,"
Mia added while glancing at the clock.
"Look, it's already past eleven-thirty. Not super late yet, but still late enough."
Rosalie finally looked up from her notes.
"I know… I just want to finish this part first. If I stop now, I'll lose the entire chain of thought and have to restart from the beginning tomorrow."
Mia sighed dramatically.
"No one can win against Rosalie when she enters genius mode."
Then suddenly, her eyes widened as if remembering something important.
"By the way… when did our precious princess Lily come back? I totally passed out earlier. She probably ordered wine and forgot to wake me up again."
Rosalie chuckled quietly.
"She came back pretty early. Said she was studying at the library. Around eight-thirty maybe. You were already asleep."
"She seriously didn't wake me up?"
"She searched through your bag and stole one glass of wine though,"
Rosalie replied calmly while pointing toward the refrigerator.
"The bottle's still there."
"I knew it…"
Mia groaned dramatically.
"That traitor."
Rosalie simply smiled before returning to her calculations.
Mia leaned closer over her shoulder, studying the notebook carefully.
"…Wait. Rosie… is this Kinematics?"
Her brows slowly lifted.
"Denavit–Hartenberg Parameters? Aren't these the matrix equations used for calculating rotational angles and distances between robotic joints?"
Rosalie paused for a second before quietly closing one of the books.
"It's for something important,"
she answered carefully.
"But I can't let people know about it yet… especially Ethan."
Mia immediately straightened.
"Ah… okay. You don't have to explain if it's dangerous."
Then she grinned softly.
"Though honestly, all your secrets are completely safe with me anyway."
Rosalie looked at her friend for a moment before smiling faintly.
"Still… go sleep first."
"Nope,"
Mia refused immediately.
"I'll sit here and keep you company. Watching you draw weird robot sketches is surprisingly entertaining."
Rosalie laughed quietly under her breath.
"Then help me with something."
"Hm?"
"You're better than me at applying theory into practical mechanics,"
Rosalie admitted honestly.
"Can you explain Dynamics and Torque distribution again? I want to apply them to the robotic arm and wrist system."
Mia immediately pulled a chair beside her.
"Ohhh… now we're talking."
She grabbed a pencil and flipped one of the notebooks toward herself.
"Okay. Let me try calculating first. Then you can double-check everything afterward. I was actually thinking about testing this theory in the lab tomorrow anyway."
Rosalie nodded quietly and resumed sketching.
The robot's head structure had already reached a stable phase. What remained now were the torso and arm assemblies—the most complicated sections of all.
Thanks to Julian's medical knowledge, Rosalie had started understanding human anatomy on a far deeper level than before.
The human arm was not simply a moving limb.
It was an incredibly complex joint system.
The Shoulder Girdle consisted of the clavicle, scapula, and humerus working together in synchronized movement. The major muscles responsible for arm motion were the Biceps Brachii, Triceps Brachii, and Deltoid muscles.
To recreate natural human movement inside a robotic arm, the system needed to support rotational motion, lifting movement, twisting motion, and swinging balance simultaneously.
That required a multi-axis rotational joint system.
But movement alone wasn't enough.
The true challenge lay in creating fluidity.
To achieve that, the robot required precise Torque Distribution systems, Motion Feedback Processing, Real-Time Positional Correction, Inverse Kinematics calculations, and Dynamic Load Balancing.
Torque itself was rotational force.
When a human arm moved, the force generated around the shoulder, elbow, and wrist wasn't isolated. It distributed naturally throughout the connected joints and muscle structures, allowing movement to appear smooth and effortless.
Human motion looked simple only because countless micro-adjustments occurred every second without conscious thought.
Rosalie wanted to recreate that perfection artificially.
Not just movement.
Not just mechanics.
She wanted to create something that could move so naturally that people would forget it was a machine at all.