Edgewater resident Mary Grzesik took this photo of a compass drawn in the sand from above the 20th floor of her high-rise. View Full Caption DNAinfo/Facebook

EDGEWATER — When Mary Grzesik looked out her lake-facing window around 9:30 a.m. Tuesday from above the 20th floor of her high-rise, she was surprised by what she saw in the sand below.

"I thought they were really cool," said the 36-year-old Edgewater resident. "They were large, they were accurate, it kind of looked like someone took a big stamp and pressed it in the sand."

Far below, in the sand directly east of Lane Park, 5915 N. Sheridan Road, was a highly detailed sand drawing of a compass, complete with swirling designs and respective cardinal directions.

Grzesik, who lives in a building near Sheridan Road and Thorndale Avenue, said this is the first time she's seen anything unusual at the beach since her move there in April. She said she was so intrigued by the formation, she got up again early the next day, this time around 8:30 a.m., and sprinted to her window with the hopes of catching a glimpse of another.

This photo, taken by Edgewater resident James Finn, shows someone reconstructing the triangular drawing in the late afteroon on Wednesday. View Full Caption DNAinfo/Facebook

She wouldn't be disappointed.

"I was like, wait a minute there's something in the sand!" she said.

The second design, this time in the form of a mobius-esque triangle, was already settled into the sand.

Grzesik she took her findings to social media, where neighbors speculated who or what might be behind the etchings, with some noting the "alien-like" formations closely resembled "crop circles."

"I think it's someone who's very creative; obviously they've done this before," she said.

Grzesik noted that by around 11 a.m. the formations usually disappeared, kicked into the wind as school let out at nearby Swift Elementary and school children played at the park.

One neighbor, James Finn, 35 of Edgewater, who lives on the 20th floor of a high-rise also at Sheridan and Thorndale, said he saw Grzesik's posting of the formation photo and decided to keep an eye out.

On Wednesday, as he took a brief smoke break from his balcony around 4 p.m., Finn said he, too, noticed the unusual sight in the sand. What's more, he said, there appeared to be a single figure at work rebuilding the creation at the time Finn snapped his photo.

Jerry Goodman, assistant to 48th Ward Ald. Harry Osterman and liaison to the Chicago Park District for the Sheridan Road and lakefront parks, said his office learned of the formations on the beach Wednesday, but had no information on the artist yet.

"They are pretty cool," Goodman added.

As of Thursday evening, a new creation had not been spotted.

"I was kind of bummed," Grzesik said.

For now, while some residents continue to comment on the photos, others like Grzesik say they will keep watching the skies — and sand.

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