My daughter asked me: “Daddy, what’s the tallest structure we can build with those 4 pieces?”

Her only rule was: “the structure needs to stand on its own.”

So here is one simple solution:

But we can do better:

The pink circle is hidden between two pieces, and it adds to the height

And better:

The pink circle does not add to the height

Now, stop!

Can you think how you would make it even higher?

Well, below was our best solution: