Great Idea for Toddlers / Preschoolers

I know that a huge challenge for many of us is how to keep the littles busy and out of trouble while we work with the olders. I just got this idea in my email this morning from education.com and it's wonderful! I'm going to have to do this and it will be so good for the Princess. Of course, keeping big brother focused on his work will be the new challenge because he'll want to play with her - LOL! Actually, it might be a good project for him to set up for her and they can both play while I get some work done. OK, I'll quit thinking out loud...
Enjoy this idea. Let me know how it works for you. I'll try to do this today and post pix asap.  

Pix as promised. This kept her engaged for approximately an hour. Lessons learned: Popcorn kernels make a very satisfying sound, this worked on more motor skills than I expected, food safe dye will wind up on hands.