The system uses magnetic levitation. It can be more efficient than a system of conventional elevators, not primarily because of speed, but because of the ability to move units across shafts and stack them when needed.
It’s time for some convex optimization.
It was a very curious scene indeed! We came upon it during our vacation down south in the South Carolina Lowcountry, on Hilton Head Island, along the eastern shore of the US. It is an area of great natural beauty, of woods and waterways, and of human habitation that tends to blend in with the surroundings. The thick vegetation, and especially the old oak trees with the Spanish moss hanging off the branches, gives the place a unique look and atmosphere (especially in the fog). Birds of different kinds, including egrets, herons and cormorants, abound. The squirrels are constantly creating a racket and startle you as you walk through the neighborhood. It is a good place for a vacation.
Soon after our arrival we learned that alligators were quite common in this area.Having come from parts of the country where alligators are not a common sight, the opportunity to see a real live gator in its natural surroundings was something special to be hoped for and anticipated. During the early days of our stay we did see a few of them with their heads and noses sticking out the water, but it was only towards the end of the trip that we got a good view of them out of the water. (There are a couple of related pictures in my earlier blog about our vacation.) But the big surprise was on the day before we departed the island, when we came upon this large alligator sunning itself on the shore on the other side of a canal. Perhaps you did not notice it or pay attention to it when you chanced upon the relevant picture in my blog about our vacation, but there was a big turtle sitting next to the head of the alligator.
You have to picture the scene, where these two very dissimilar creatures are next to each other, and nothing is moving except for perhaps the head of the turtle that is turned to look at the disturbance that we are causing from the far shoreline. The gator can perhaps see what is going on without moving its head.Here is this huge gator that in my imagination (and to my limited knowledge) looks like an old male. Here is this big turtle (which may be a yellow bellied slider) sitting next to it. Nobody is moving. It is quiet. It is a very peaceful scene.The human imagination wants to believe that these two creatures are two old and wise friends who are simply hanging out with each other. But alligators can also eat turtles. They are capable of cracking the turtle shells.
The experts tell us that these creatures are not capable of thinking the way human beings do. I am sure people who study these particular creatures more closely have a logical explanation for the scene that was playing out before our eyes. Indeed, for all we know, such a scene may not be uncommon to the locals. But for those of us who are less informed, we will have to use our imagination. The turtle and the gator must simply be good old friends. It is really a moment of magic that defies our natural instinct based on what we have been taught all our lives. Indeed, for some us, the opportunity to simply see an alligator in its natural surroundings is in itself a magical moment!
The tree had seen many seasons pass by. Its days as a young sapling were barely a memory. It had lived through many times of change, and survived many years, to grow into a fully formed master of the jungle, multi-branched and majestic in its span, held up by a strong and solid trunk, and fed by its well-spread and efficient roots that picked up nourishment from Mother Earth.
As a young plant growing up the thick woods, there was an element of uncertainty about its ability to survive. There were times when there was a doubt whether it would make it through the season, or even through the day. In those days, it did not have the strength and the knowledge to endure on its own. It was dependent on the creatures that lived around it, it was dependent on the earth and the skies – it was even dependent on the winds that blew through its young and growing branches.
But now it was a mature and strong ruler of its domain. It had seen many things, and gone through many experiences, both good and bad. It had become a wise one. (Of course, it had not traveled far and wide. It was a tree, for heavens sake!) It had known troubles and setbacks, and survived to fight another day. It had seen change, both in itself and in the things around it. It had known both happiness and sadness. It had experienced the beauty of the sunrise and the sunset, it had withstood many a storm that shook its trunk and threatened the very core of its existence. When one of its branches suffered, perhaps from a bolt of lightning, or perhaps from an illness in its leaves, the tree found a way to survive. It could thank its strong roots and its other healthy branches that worked to keep it alive – each branch vibrant with the new leaves of spring, the flowers of summer, the multicolored hues of fall, and the whites of winter. The birds resting on its generous branches, singing happy songs, gave it pleasure. It had learned that the dark and gloomy winter that left it cold and shivering, would eventually be replaced by the rebirth in Spring. It knew that if trouble came to pass, it could survive because it had survived similar troubles in the past. Nothing could bother it. And it wished to be sure that its wisdom was passed along to the young ones.
It wanted to make sure that these young ones, the seeds that grew into saplings, and the saplings that grew into stronger plants, and then into trees, would know how to face the world, and also learn to recognize the gifts provided by the earth. It wished to show them the safe path amidst the dangers that lurked, and it also wished to help them experience all the good things that it had itself experienced. It knew that it had to be patient in its endeavors, and that it would not always be successful. It also knew that there would be a time when it could teach no more. It watched over the seed that had fallen far away, and hoped that it would still be able to learn in spite of its distance – that it would still listen, that it would realize that nothing survives in this world on its own.
It knew that its time would eventually pass, and that its roots would not be able to sustain it forever, but this bothered it little. It had survived to see what it wanted to see, and experience what it wanted to experience, and it had left its legacy behind in the trees and plants that had risen from its seed. It had helped many a creature of the woods, whether it was one that needed protection, or even some food, or whether it was one that just needed a comfortable trunk to rub itself against to remove the itch from its back. It had served its purpose and had left its mark on this earth! It did not matter if it happened to be cut down the next day. It did not matter if a flood washed it away along with its roots during the next thunderstorm. It was content.