A reader noticed a device that looks like a child's whirligig atop one of the short light poles at the Civic Center shuttle turnaround on the 16th Street Mall. It spins when the wind blows. The reader wanted to know what it is and why it's there.

That device is an anemometer, or wind gauge, and it's there for the very practical purpose of keeping shuttle riders from getting soaked, said RTD spokeswoman Daria Serna.

When a fountain was built in the center of that shuttle loop in the early '80s, the anemometer was installed and linked to the fountain to automatically shut it off when the wind reaches a certain speed.

The fountain has been off for several years because of the drought, and the RTD hasn't decided whether it will function this summer, Serna said.

Here's another question to keep you busy while you're eagerly awaiting that decision:

You often hear the word virtual, as in the plan to build a virtual fence between the United States and Mexico. What does virtual mean in this sense? - Harry

Post your responses at the Ask! blog, blogs.rockymountainnews.com/denver/ask by clicking on the question you want to tackle and scrolling to the bottom. Or post your own question by clicking on the prompt to the left when you get to the blog.