On your next trip to the shore, gather some seaweed to transform into an undersea still life at home.
At the beach, collect small pieces of colorful seaweed in a bucket with enough salt water to cover them.
At home, gently rinse the pieces in a colander, then place them in a tub of fresh water.

Trim a sheet of 100 percent cotton paper to fit a standard picture frame. Arrange the damp seaweed on the paper.
When you've finished composing your picture, place the paper on a stack of at least 5 sheets of newsprint drawing paper. Cover the seaweed with a piece of waxed paper, a few more sheets of newsprint, and a stack of heavy books. Replace the newsprint every other day until the seaweed is completely dry (in about 2 to 3 weeks). It should adhere to the paper, but if a piece is loose after it dries, glue it down.
To preserve your artwork, frame it behind glass and keep it out of direct sunlight.