Tony hummed Jingle Bells off-key as holographic schematics danced around him. His eyes flicked to Leon squinting at basic mechanical diagrams, and a smirk bloomed. "Don't strain yourself, little brother. Even Einstein needed naptime."
Leon didn't look up from the floating screens. Text scrolled at hypersonic speeds – metallurgy treatises, plasma dynamics papers, even Stark Industries' rejected "Edible Circuitry" patent. His pupils darted like quantum particles, absorbing knowledge faster than JARVIS could buffer.
By hour three, Leon's StarkPad glowed with completed tutorials:
✓ Advanced Repulsor Theory
✓ Neuromuscular Interface Design
✓ How to Survive Your Genius Sibling: For Dummies
"Done." Leon rose just as Tony stabilized his boot thrusters mid-air. "Your turn to play student, Professor Stark."
Tony landed with a clatter. "Student? You couldn't differentiate a capacitor from a—"
Leon's finger ignited, tracing a perfect Fibonacci spiral in the lab's titanium floor. "Gyroscopic stabilization fails above Mach 2 because you're using 1980s inertial dampeners. Upgrade to vibranium-alloy gimbals here..."
Tony's wrench clanged to the floor. The equations hovering above Leon's palm weren't just correct – they improved his life's work.
"Photographic reflexes?" Tony's voice cracked. "That's cheating!"
"Call it... accelerated tuition." Leon tossed a graphene chestplate into the molecular forge. "Your lecture on ego-driven engineering starts in 5...4..."
The lab descended into beautiful chaos. Tony's "genius hour" became a live commentary track:
"Impossible! That alloy ratio would— wait, why's it working?!"
"Stop bending physics! That screwdriver's for left-handed circuits!"
"JARVIS! Am I hallucinating? Run a sobriety scan!"
At dawn, the Mark II stood complete – sleeker, deadlier, and inexplicably rose-gold. Tony gaped at the armor, then at Leon casually forging a nano-circuit with his heat vision.
"This..." Tony gestured wildly, "this is intellectual property theft!"
Leon buffed the chestplate with his sleeve. "Knowledge wants to be free. Also, you drooled on the blueprints at 3 AM."
As the first sunlight kissed Malibu's cliffs, JARVIS broke the silence: "Shall I prepare the 'World's Okayest Engineer' trophy for Mr. Stark?"
Tony's groan echoed through the lab. Somewhere, Howard Stark's ghost chuckled into his martini.