Like most people, 40-year-old Andres Amador likes spending hours on the beach doodling on the sand. However unlike most, he does not draw random scribbles, but giant masterpieces that can measure as big as 300 by 500 feet.

The San Francisco-based artist say that he got this idea from the mysterious crop circles that seem to appear out of thin air in many countries around the world. One day, when he was illustrating the concept to a friend by sketching it on the sand in Kauai, it suddenly occurred to him that he could replicate the 'alien crop circles' on sand and, thanks to San Francisco's wide sandy beaches, they could be as big as he could make them - That realization was 12 years ago and the artist has never looked back since.

While a majority of his amazing artwork is still created beneath the city's Sutro Heights on Ocean Beach, he has also been commissioned to etch on beaches around the world by companies like Red Bull and even, been invited for international competitions.

The artist, who gets his design inspiration from things around him, begins by drawing his masterpiece into his sketchbook. He then crafts the image onto his computer and practices a few times, to ensure he gets the design right.

Once ready, he waits for the perfect day - Usually the day of or following a full moon when the ocean tides are at their lowest. Even so, Andres knows he only has limited time before the tide washes out the masterpiece and therefore, usually allows himself just two hours for each creation. While a lot of times he works alone, if the design is massive, he does invite friends and sometimes has as many as 25 people 'raking' away diligently under his direction.

The only tools the green artist uses are rakes, ropes and stakes. He begins by first sketching the outline of the darker sections with either the rope or stake. Then, he takes the rake and drags it across the sand surface around the lines, to expose the wetter and therefore darker sand that lies below. The artist says creating the patterns is the easy part - it is deciding which area to shade or darken that sometimes takes him some time to figure out.

The fact that his painstaking work lasts for only a few hours and sometimes even less than that, does not seem to bother this artist. To him, the water just clears up any mess he leaves behind and creates a clean canvas for him to 'paint' on again. And, even if the artwork does not quite turn out right, Andres is just thrilled that his work allows him to spend the day walking around on the beach barefoot.

Andres is not the only artist to use the sand as his canvas - Jim Denevan, who also resides in California has been doing the same thing for many years - What would be cool is if the two created a piece of sand art together.