A pop-art icon, Robert Indiana’s work often revolved around monosyllabic words like Amor and Hug. In 1964, at the New York World’s Fair, he installed a flashing 20-foot electric sign that read “Eat.”

Alas, the world wasn’t prepared for Indiana’s groundbreaking use of popular signage. His electric sign was unplugged almost immediately because too many people were drawn to it looking for food.

The world was, however, ready for Indiana’s most iconic image, LOVE, a 12-foot-tall steel sculpture for the Indianapolis Museum of Art in 1970. So popular was the LOVE image, which first gained recognition when it was used on the Museum of Modern Art’s 1965 Christmas card, that in 1973 the United States Postal Service created a LOVE postage stamp. The stamp was such a hit that 300 million stamps were printed. 

The widespread appeal led Indiana to create more versions of the LOVE sculpture, many of which are on display around the world in parks and squares.

In different presentations of LOVE, Indiana used a range of contrasting colors to highlight the word. But the colors of the first version hint at the deep meaning the work had in the artist’s own life.

“The red and the green came from the Philips 66 gas sign,” Indianapolis Museum of Art curator Martin Krause told National Public Radio in 2014. “His father worked for Philips 66, and he remembered that combination; it fixed itself in his mind. And when he began making the LOVE paintings in 1965, his father died. So the red and green of the LOVE painting, silhouetted against the blue Indiana sky, is in memoriam of his father.”

Born in New Castle, Ind., on Sept. 13, 1928, the artist grew up as Robert Clark. He would change his surname in tribute to his home state. Indiana, who once called himself simply an American sign painter, died in 2018. He was 89.