Sensory bottles! They used Voss water bottles. Not sure where to find them but any water bottle will work. use mineral oil for a way to slow down the materials in the bottle. I usually do 2/3 water to 1/3 oil. Can also do just rice and small objects for I-Spy bottles.
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 pages for different shapes to learn while playing