Beautiful Artwork in the Night

Every night I know they're there. From the patio I can see the light shining on three spiders that have chosen our yard for their own keeping. I see them. Only them. They seem to be moving around in mid-air. They layer their webs across the yard, making certain not to interfere with another's territory. Their artwork completely invisible as I watch. I know not to move around the yard after dark without a flashlight. If there are these three, there must be more. When do they start working? How late do they continue to work? How do they even get started? What it must be like when they're making their giant leaps on the air to attache that first strand of silk. By 8 o'clock the next morning, all signs of them are gone. But I know they'll be back tonight.