Just walk toward North Main Street from the center of the square, and look for the three circles near the corner. Turn left and search for the trumpet.

Take a left, walk past two planters and there it is: A “prehistoric duck” etched into a paving stone, near a rhinoceros and other designs. They are a few of the dozens of symbols hidden in the stones around the city’s square.

When Bohlin and Powell Architects redesigned the square after Hurricane Agnes, they included nearly 150 designs carved into stones. As pedestrians walk through the space, they pass over modern petroglyphs showing symbols of nature, technology, architecture and local history.

“They are really one of the unsung features of the 1970s redesign of the square, one of the wonderful little secrets of downtown. In many ways, it’s this scavenger hunt built into the design,” said Larry Newman, executive director of Diamond City Partnership.

Some designs are easy to identify. Images of leaves dot stones throughout the park. A cat, a pretzel, hands and lips are in the seating area; and crops like strawberries, onions, melons, apples and peaches are hidden among the planters on the edges of the square. Elsewhere the sharp-eyed pedestrian can spot a beehive — a symbol of the city — and a map showing the outline of the Susquehanna River in the area.

Other carvings are less obvious. One symbol honors the National Parliament designed by architect Louis Kahn in Dhaka, Bangladesh, one of several images inspired by architects. Another unclear carving is explained on a map as “crunched person.”

The profiles of people in one corner show not just anyone, but the outlines of Peter Bohlin and Dick Powell, who started the architecture firm that became Bohlin Cywinski Jackson.

The firm has a map of the petroglyphs. It shows where you can find designs around the now-dry large and small fountains, walkways, planters, corners and small sunken seating area.

Placement might not be exact, but a recent search found many designs can be tracked down using the map.

Some designs might be missing, or just hard to spot. They could have been moved, or a contractor might not have had exact directions for where to place special stones.

In some places, the stones have come up, and in the southeast corner, an asphalt mix fills in spots.

Some stones need to be reset in the ground, but the granite the designs are etched into is durable and will last for longer than pavers or concrete, said architect Nicholas Snyder of Bohlin Cywinski Jackson.

The symbols are a way to connect people to the square, he said.

Consider a helicopter etched into one of the stones. It might remind one person of the helicopters that helped after Hurricane Agnes. Another person might recall choppers from the Vietnam War. Someone else might see another story.

“Then people start asking, ‘Why is it like that?’ And the next thing you know, you have people engaged in Public Square,” he said.