LONDON, England (CNN) -- On a windswept beach on the Dutch coast, Theo Jansen's Strandbeesten (beach animals), stalk across the wet sand. It's hard to know quite what to make of them.
They walk among us: Jansen's unique vision of mechanical beach animals has been an evolving project.
Are they art, engineering or nascent forms of artificial life? They straddle all these definitions, just as their creator has brought together his background in science and art to create a curious new form of mechanical life.
Jansen gave up studying a degree in Physics in 1975 to become a painter. Five years later he returned to explore his earlier life by designing and building a 4 meter-wide flying saucer. It actually flew, taking to the skies over Delft, Netherlands, confounding and scaring the locals.
But for the last 17 years he has been developing his animal-like kinetic sculptures made from plastic tubes and powered by nothing more than the wind.
"Being an artist you want to do things, there's not really a reason, you do what you feel and you don't usually ask why you do them. If I look back I think everyone wants to be immortal and I think this is a way for me to do this. It's the same thing as making children; you put down a genetic marker," says Jansen.
Working from his studio on an isolated, grassy embankment between a highway and a canal just outside Delft, Jansen is a cross between a beneficent uncle and H.G Wells' fictional Dr Moreau when speaking about his creations, often using the language of Darwinian natural selection when explaining the evolution of his project.
Built from yellow plastic tubing, the kind usually used to insulate electrical wiring, and nylon string, Jansen's creatures are a complex design of rods and strings. There's something primal the way they look, like the skeletons of large altered beasts, but when in motion take on a living quality that is both amazing and amusing.
"When people see my animals they look happy. The beasts represent life, more or less, and I think even children recognise what I'm doing."
It's taken a long time to get where he is today. In the early days, his challenge was working out the algorithm that would make the animals first stand and then walk. Creating a computer program on an old Atari, he finally struck upon the "11 holy numbers" that set the rules of the distances between the joints and tubes.
"Real animals have the same mechanical principals, which I think is why the Strandbeesten look like real animals.
"When I make an animal, I'm not making art -- I don't want to be creative. Just like real evolution it functions, but it also looks beautiful. Nature didn't try and be creative," he says.
From Animaris Geneticus Ondula that resembles a skeletal high stepping chorus line, to the lumbering three-ton Animaris Rhinoceros Transport that can carry a passenger, the principles of movement and engineering are the same for each sculpture.
Jansen hopes that one day they will be highly evolved enough to live in herds on the beaches, able to fend for themselves without the need for human intervention.
By setting them in competition against each other he is able to test what features work best in the often inclement conditions. The animals that fall short, die, donating their DNA -- the plastic tubing and nylon string -- to create the next, stronger and smarter animal.
The latest family of animals have wings that feather in a wave motion. While making the sculptures even more intriguing there is a purpose for them; the wings help capture the wind in empty lemonade bottles -- the animals' "stomachs" -- that can then be stored and released when there is no wind. They can't move for long on this energy, but it is another step in their evolution.
Other sculptures have a water feeler, a tube that sucks in air, but when it feels the resistance of sucking in water from the sea it changes direction. The "brain" is a binary step counter, so the animal can tell where it is in relation to danger in the form of the sea and the sand dunes.
They still need a lot of help from Jansen to survive unaided, although the latest breed of Strandbeest can hammer a pin into the ground when the wind is too strong and it is in danger of being blown over.
The philosophy behind the beach animals has evolved just as Jansen has developed them.
"It's not important just to make things, but to reflect on them," he says.
While there is a theme of melancholy about his creatures and their struggle to survive, Jansen himself is an optimist -- it would be hard to spend 17 years working on a project, mostly alone, without a positive view of life and the mysteries of existence.
"I see things, even if they are just illusions, I start on them and I think that's an effect of optimism. I'm not that much of an engineer, I'm just a trier.
"Of course I want to know what the causes are of this great adventure in life. I don't know why we're here, but I understand bits. It's like lifting the veil now and then. I've just written a book about my work and ideas, it's called 'The Great Pretender,' that's me of course," he says smiling. E-mail to a friend