Put rice in 5 different solo cups then you can make the that way as well also our kids had fun with putting them back in 10 min every day my two older ones separated the rice and they glued it to page (Bottle Bag Sensory Play)
DIY Sand and Rock Box by FSPDT. Gdjk -> made this with toilet rolls (aka tunnels) and moon sand instead of play sand. My son loved playing with it. The moon sand cleans up nicely indoors but play sand will be easier to play with when using the small cars.