The Brief
An interviewer once asked: "You've got an island and ten thousand people a day. How do you design the amusement park?" It's a thinking question — there's no single right answer. But there's a way to think about it that separates the engineers from the dreamers. This capstone is that question, made buildable.
The Three Budgets
Every decision on this island lands in one of three ledgers. The Energy Budget — every ride, ferry, pump, and light either draws power or recovers some, and at the end of the day the island has to make more than it spends or import diesel to cover the gap. The Water Budget — fresh water comes from a solar desalinator and gray-water recycling; nothing is wasted, everything is tested coming in and going out. The Experience Budget — none of it matters if ten thousand people don't have a great day, because an empty park is the least sustainable thing of all.
What You'll Do
Across the next tabs you'll size the island's energy generation against its draw, design the closed-loop water system, choose which rides to build and how aggressively to recover their energy, and finally defend the whole design with a composite score across the three budgets. The trick — the thing Okafor is really testing — is that you can't max all three. Push experience too hard and the energy budget collapses. Starve the rides to balance energy and the park empties out. The grade is in the honest tradeoff.
The Ground Rules (Non-Negotiable)
No grid connection — the island makes its own power or burns diesel and takes the penalty. Zero single-use plastic — guests bring their own cups, the park sells reusables, no straws. Carry-on / carry-off — everything biodegradable is composted on-island; everything else leaves with the guest who brought it. Any tree removed for construction is replaced with engineered habitat. Every building is painted to dissolve into the landscape — no single flat color anywhere.
Energy Budget
Ten thousand guests, a fleet of ferries, a steam-electric train, a dozen rides, pumps, kitchens, and lights. On the generation side: island solar, ferry-mounted wind, regenerative braking, and micro-hydro on the flume. Balance it. If you fall short, the diesel generator covers the gap — and your carbon score pays for it.
Generation
Demand
Daily Energy Ledger (MWh)
Why Regen Braking Is the Quiet Hero
A roller coaster spends most of its energy on the first lift hill. Every descent after that is gravity giving the energy back — and a maglev coaster with regenerative braking captures a real fraction of it instead of bleeding it off as heat in friction brakes. Crank ride intensity and regen together and the rides nearly pay for themselves. This is the same physics as the steam-electric train recovering energy on its downhill grades, and the same idea as the ferry charging its batteries from wind while it's underway.
Water Budget
No mainland water main. The island makes its own fresh water with a solar-powered desalinator and stretches it by recycling gray water for irrigation. Drinky watches everything coming in; Stinky watches everything going out. Every fountain on the island shows the live numbers.
Supply & Reuse
Demand
Daily Water Ledger (m³)
Drinky In, Stinky Out
Mira Bowles's monitoring systems run the island's water the way they run eleven Tennessee water systems. Drinky watches every input — desalinator output, recycled gray water, the fountains guests drink from — flagging trends hours before they become problems. Stinky watches every output — irrigation runoff, the brine the desalinator rejects back to sea, any discharge near the ocean farm. The live readings show on every fountain screen: when a kid fills a Stanley, the wattage and the water quality are right there to read.
The Ocean Farm Constraint
The fish farm and ocean-farming beds sit a mile offshore in relatively shallow water — which is exactly why the desalinator's brine discharge matters. Reject brine is saltier and denser than seawater; dump it carelessly and it pools on the bottom and suffocates the very beds you're farming. Stinky watches the discharge salinity and the design diffuses the brine across a wide outfall so it mixes before it settles. The water budget and the food supply are the same problem viewed from two ends.
The Rides
Every attraction is a physics lesson the guest doesn't know they're taking. The display boards are part of the ride — live G-force, live RPM, live wattage recovered. The rides that draw the most power are also the ones that give the most back.
The Midway & The Quiet Room
The fair midway runs the honest classics — ring toss, the duck pond, the disc-cover game, dart-and-balloon with a screen showing each dart's aerodynamic path and speed. (The trick on the darts is the shadow: catch the shadow and you know where it lands.) And tucked off the midway, the Butterfly Network Reading Room — air conditioning, a wall of gold-taped books, free water, and absolutely nothing you have to do. The most sustainable square footage on the island is the part where a tired kid sits down with a book and a cold drink and just breathes.
Defend It
Okafor and six deans are in the room. Your energy budget, your water budget, and your guest experience are all on the board at once. Hit "Run the Defense" and the island runs a full operating day against your settings. Then live with the grade — and the honest tradeoff it reveals.