Building Towers

I found this tower building toy at a thrift store.  I'm trying to use less plastic toys but this one challenges the children in different ways.  First they have to figure out how to set it so when they push the button to knock it down that it will.
  
Then they have to work on building it up, balancing each layer on top of the other so they don't fall before they want it to.
                     
  
I encouraged the children to show me how to build a tower and I copied theirs.  I noticed soon after a couple of parents doing the same thing.
                   
The surprise, when they press the X, and watch the tower tumble was the best part.