Homemade Horse Sand School!

These are the two arenas I have made! The smaller one is my riding school and the larger on is used for a dressage arena or a show jumping arena. There are made out of cardboard, glue and REAL sand, all I did was...
 cut the cardboard to size,
 cover in glue,
 cover in sand,
 leave to dry,
 shake of loose sand,
 spray glue to secure sand,
 leave to dry,
 repeat spraying and frying process till no sand falls of!
If you would like to a video tutorial on how to makes this please comment below!