The gravel formation is created by raking the gravel material. Also the formation of the lines in it are created by the rake and thus are not permanent. Hope this helps...thank you for the comments. ---AguaFina

beautiful, but you wouldnt want to have young kids with access to the rake

what is the sand like material? Is it sand, crushed gravel?

Armina: It is crushed granite. We use a mixture of two different sizes of poultry grit in order to achieve the look. It is able to hold and give beautiful dimension to the lines when raked.