Busy Bag with marbles & bath grips

I bought a 4 pack of these bath grips for the tub. You know, the things that prevent slipping?
They don't work in our tub and were just laying around. 

Now they have a purpose!!

*UPDATE*

We started putting this activity on a tray. 
Helps keep the marbles in one place!

(old way)

*I still keep the marbles in a baby food container*