Set it up on the roof, and the wind and sunlight will provide electricity. When you come back at night, the lights will be on again.

Set it up on the roof, and the wind and sunlight will provide electricity. When you come back at night, the lights will be on again.

In the morning, as you leave, you glance up at the roof. The windmill is turning, and the planks are drying in the sun. Without thinking much, you lock the door and go to the fields. You're busy all day in the fields, the sun blazing, the wind howling, and you're exhausted. You don't have time to think about home.

When you return in the evening, it's already dark. You push open the gate and pause—the lights are on. They weren't turned on before you left; they were turned on for you while you were gone. The windmill turned all day, the planks dried in the sun all day, storing up electricity all day, and when it got dark, the lights turned on by themselves. While you're not home, it's keeping watch over the house for you.

You go inside. The lights are bright, the refrigerator is humming, the phone charger is plugged in—everything is just as it was when you left. But you know it's different—this day's electricity wasn't bought with your money; it was provided by the wind and the sun. While you're out working, it does the work for you at home; when you come home tired after a long day, it has already tidied the house and is waiting for you.

This feeling is especially heartwarming. It's not just the warmth of the lights, but the warmth of someone thinking of you. Electricity is everywhere, day and night. You put the machine on the roof, and it has enough electricity for your entire life. You just go out to work, and it stays home and watches over you. When you come home at night, the lights are already on, dinner is ready, and the kids are doing their homework.

Put it on the roof, and electricity is everywhere, and when you come home at night, the lights are already on. From today onward, when you leave home, you know someone has kept the lights on for you.