A flywheel is an in-game device that keeps you topped up with energy as long as you keep moving. The more you walk, the more energy you get.
Given to every player right after sign-up. It spins up from walking and turning; at the maximum speed of 10 it hands out 5 units of energy every 5 minutes. It slows down on its own if you stand still for too long.
A bonus flywheel — bought in the shop or awarded for achievements. It has a stronger "winding", so it slows down less and runs at the maximum speed of 20, giving you 5 units of energy every 24 seconds.
The flywheel picks up speed on its own while you move between hexes. A few simple habits keep it nicely charged:
The energy fills up inside the flywheel first, and only then gets handed over to you. You see a blue ring sweeping around the spinning flywheel — once the ring closes, the energy is credited to your balance.
The energy saved up by the flywheel feeds opening new hexes, building structures, and destroying objects on the map.