He led them to a patisserie whose window display featured cakes that defied physics. Floating layers, frosting that flowed like water then solidified, decorations that moved and rearranged themselves. Inside, the smell was overwhelming in the best possible way. Chocolate and vanilla and caramel and dozens of other scents Rowan couldn't identify.
"Choose anything," Nicholas said. "And I mean anything. Perenelle and I have been alive for five hundred years. We've celebrated more birthdays than most people have memories. We know what makes a good birthday cake."
Rowan selected a cake that caught his eye. Relatively small, chocolate with what appeared to be stars of white chocolate scattered across the frosting. But when the shopkeeper boxed it up and handed it over, Rowan noticed the stars were actually moving slowly across the frosting's surface, tracing the actual constellations visible in the night sky.
"Astronomical cake," the shopkeeper explained in accented English. "The stars track real-time positions. Very popular with astrologers and diviners. Also delicious."
Back at the Flamel residence, they ate the cake in the garden as real stars emerged overhead. The cake was indeed delicious. Rich chocolate with some subtle magical enhancement that made each bite taste slightly different, like experiencing the same flavour from multiple angles simultaneously.
"I've been thinking about your telegraph device," Nicholas said. "The central hub design you sketched the other day."
"The scaling problem," Rowan said immediately. "Individual paired devices work, but creating a network requires something more sophisticated."
"Exactly. And solving that problem requires runic work that goes far beyond what we've covered this summer." Nicholas set down his fork. "The arrays you've been creating. Nine runes, maybe twelve in your latest iteration. Those are genuinely impressive. You've progressed from basic single-rune inscriptions to complex multi-tier arrays in six weeks. Most students take two years to reach that level."
"But a central hub would need what? Thirty runes? Forty?"
"Try a hundred and thirty, minimum." Perenelle pulled out parchment and began sketching. "You need separate sub-arrays for each function: maintaining sympathetic bonds to all devices, directing energy between specific pairs, preventing channel interference, regulating power distribution, containing failures. Each sub-array needs its own regulatory and binding runes. Then you need master runes coordinating everything. Multiple Gebo runes in concentric circles for routing, Jera for cycling between active connections, Ingwaz to separate channels, Ehwaz for long-distance bridging. The geometric complexity is staggering."
She drew as she spoke, and Rowan watched arrays branch and interconnect, forming patterns that made his attempted hub design look like a child's drawing.
"That's mastery-level runic work," he said slowly.
"Yes. The kind of arrays that take most practitioners twenty years to learn to construct reliably." Nicholas took another bite of cake. "Of course, 'most practitioners' doesn't necessarily include you. You've already surpassed fifth-year Ancient Runes in one summer. You understand the underlying principles, which matters more than memorizing traditional arrays."
"Fifth-year?" Rowan frowned. "I thought... the book said most of what I was doing was third or fourth-year level."
"The book was written forty years ago, and its difficulty ratings assume students are learning one rune at a time, memorizing meanings without understanding geometry." Perenelle's sketch had become incredibly complex. Arrays within arrays, runes connected by flowing lines that suggested energy pathways. "You've been designing novel arrays from first principles. That's fifth-year work at minimum, arguably sixth-year for some of your later iterations."
"How long until I could attempt the hub design?"
"Depends how hard you push yourself during the school year." Nicholas considered. "Ancient Runes is offered starting third year. If you take it then, work through the standard curriculum while supplementing with advanced texts we'll send you, continue experimenting during summers... three years? Possibly four?"
"Three years is a long time."
"Three years is remarkably fast for mastery-level runic competency." Perenelle rolled up her sketch. "Most adult wizards never reach that level. The fact that you could do it in three years, starting from zero knowledge six weeks ago, proves you're working at a level very few witches or wizards achieve."
"But there's so much I still don't understand," Rowan protested. "Energy flow optimization, recursive binding structures, dynamic adaptation arrays—"
"All topics covered in sixth and seventh-year advanced Runes, or in specialized Mastery programs." Nicholas grinned. "Which means you've got a solid foundation and a long way still to go. That's the right place to be."
"The range is still limited," Rowan said. "The audio quality is poor. And I haven't even started on the security arrays."
"All solvable problems. You'll refine it over the next few years, extend the range, and improve fidelity. Eventually, probably during your time at Hogwarts or shortly after, you'll solve the hub problem. And then you'll have created something that could genuinely change how wizards communicate."
"If the Ministry doesn't shut it down," Rowan said.
"They might try. Innovations that threaten established systems usually face resistance." Perenelle smiled slightly. "But that's a political problem, and you've got years to work on the political groundwork before you need to worry about Ministry interference."