Star Tribune file photo

Apple Inc. joined the movement to teach children how to write software by offering three-day "coding camps" free at its stores across the U.S. The camps are three, 90-minute classes for kids ages 8 to 12.

Sign-ups started at Apple's Twin Cities stores yesterday and, by this morning, only the store in Uptown (pictured above) still had slots available for the camps, which will be held in late July.

Apple stores at Ridgedale, Rosedale, Southdale and the Mall of America were filling waiting lists for kids who will be called to participate if others cancel.

The company has held teaching events for children for several summers, but they were focused on using Apple software. This is the first year Apple is offering a course in coding. TechCrunch reported it will use software from a company called Tynker to teach the concepts of "block-based coding." Kids will write programs to run Sphero robots.