Dutch architecture firm MVRDV said they proposed its “Cloud” design because it challenged the mundane shape of the typical skyscraper. A pair of luxury residential towers in Seoul would be joined in the middle by a cloud-like shape, billowing out like a tutu around two legs.

But when a press release went out about the design on Dec. 7, announcing the residences as part of a plan to extend the city’s business district, a playful cumulonimbus is not the image many saw. Instead, some were taken back to 9/11, and the smoke that filled the sky after the planes hit the World Trade Center.