Castles in the air might mean daydreams to the dictionary, but to children they are very real. Just watch a child on a beach, scooping sand, patting it down, making a thousand and one decisions about the design of the castle-in-progress without even being aware of it.

This is why I never tire of drawing children at play on the beach - there's so much more going on than meets the eye. Each child's castle is unique, a fantasy come to life. But there are certain techniques that make them even more special. On your next shore outing, take along these pointers, scooped up by my trusty beach-combing scouts:1. Find a beach with good sand. The best castle-building sand is fine, with a lot of silt (a kind of silky mud) in it.

2. Dig a hole. Don't stop until you reach the wet, heavy sand, perfect for sand castle building (the white dry stuff on top is useless for this). Locate the hole near the shoreline - but not too close, so the sand castle doesn't get washed away while still in progress. Just scoop mushy sand from the bottom of the hole for a constant supply.

3. Build. As my reporters indicate, the most serious sand sculptors stop at nothing to coax very heavy, wet sand into shapes, right in the palms of their hands. They shape the sand by bouncing it until the grains come together like little flapjacks, then they lay these down as "bricks." They drizzle wet sand so that it resembles a pyramid, then pack it down into a basic castle square. Or they let it drip from their fingers into skinny mounds, to add tall, slender features like towers.

Of course, I see nothing wrong with simplifying your castle building project: Just unmold wet blocks from pails and kitchen plastic containers and use smaller, more unusually shaped containers to build your towers and turrets.

4. Decorate. All of this will soon dry, so castle makers must act quickly. Seasoned builders take along a pail full of ordinary utensils - spoons, forks, pastry brushes - to add the details. Bring along a few cookie molds besides to "stamp" shapes into the sides of the castle. Add finishing touches just by searching the shoreline: beach grass "flags," seashell parapets, starfish door decorations and tiny ladders lashed together with sea grass.

5. Stand by your sand. Half the fun of building a sand castle is waiting around for people to admire it. So schedule in plenty of time for just gazing at your handiwork.

Of course, tomorrow the sand castle will be pretty much gone, but rest assured it will not be forgotten by children. In their minds it will grow to twice the size it actually was - the perfect model for next year's dream castle.

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