Sergels torg is home to one of Stockholm’s main squares and a busy train station. It seems like a perfectly normal place, that is, until you notice a flattened birch tree smushed between two pieces of glass.

Rest assured, this isn’t a real tree in peril. Swedish artist Ronald Persson created this tree, together with a second one, to liven up the station. The lifelike trees, which sprout from what look like flattened wheelbarrows, are made of silicon.

The art piece is quite subtle, resembling a tree on the first glance and then drawing more attention on the second. It’s not uncommon to see people glance at it with a confused look on their faces, just like Persson intended.

A squished tree isn’t the only oddity hiding in the square. There’s a galosh encased in the glass on the other side.