Rainbow Cone marks 100th anniversary serving up its signature sliced and stacked treat

To the uninitiated, a Rainbow Cone with its five colorful ice creams stacked in a seemingly gravity-defying way might seem like a recent Instagram-inspired creation. But Chicagoans, especially those on the South Side, know that the Original Rainbow Cone shop and its photogenic namesake are local institutions that predate social media — along with cellphones, computers, the first fully electronic television, microwaves and a host of other modern-day conveniences. Launched in August 1926 in a…