The beach is the ultimate ever changing canvas, you can draw shapes untill your hearts content, then take a photo, put your name on it and do it all again.
You can bring your own drawing equiptment like a umbrella end, a spade edge, or use the natural tools around, a tree branch, a shell, your finger or Big toe.
There is no wrong when when it comes to the freedom to draw, try expressing yourself, if you don;t like it, start again, the tide will wash it away.
Draw somthing really big, then find a vantage point from up high and take a photo of it.
For young ones, you can climb on Dads back to get a high photo of your art work.
Have fun, remember to cover up.