This sensory activity exposes the child to a variety of textures and helps with desensitization.
Fill the plastic container with rice and/or beans.
Hide the puzzle pieces in the rice/beans mixture.
Have the child search for the pieces using his hands (if the child is tacitly sensitive, you may try to put gloves on his hands or let him use tongs or tweezers).
Once the child has all the pieces, ask the child to put the puzzle together.