It looks like a stream of water, running straight between two large rocks – but as you walk along this sneaky mirror, in the grass outside the Rijksmuseum, you have your head in the clouds.

In the 11^th free, garden exhibition outside the national museum, Korean artist Lee Ufan has created what he calls the “art of the encounter”.

A scattering of installations of rock, steel, water and mirror outside, and two works inside, are intended for visitors simply to experience. “Just walk around, touch them, feel them, and enjoy my artwork,” he said, through a translator, at a press opening on Tuesday morning.

Lee, born in 1936, moved to Japan at 20 and now has a studio in Paris and private museum in Arles. He was a central figure in Japanese and South Korean avant-garde art movements exploring relationships between material objects and space, and monochrome painting. But although he now often works with rocks and the “children” of rocks – elements like steel – as ways to explore the infinite, he stresses repeatedly it’s not about his words. “Without any expectation, see them, enjoy them, make your feeling free!”

One of the highlights of the summer in the Rijksmuseum in Amsterdam is a series of entirely free modern art exhibitions, open to the public to wander through thanks to donations by the Don Quixote Foundation, Rijksmuseum Fund, Pon and the Rijksmuseum Club. Previously, the public gardens have shown work by Henry Moore, Joan Miró, Barbara Hepworth and, last year, British artist Richard Long.

“This is a present to the city, for everybody to enjoy, free,” said general director Taco Dibbits. “Lee Ufan is an international pioneer in sculpture and a philosopher. He’s a man of few words, but in his modesty, he said [to me]: I don’t want a representation of myself in sculpture. I want my work to be a wonder of space.”

The Sky Road – that mirror in the grass – certainly invites childish wonder from visitors. The Infinite Garden is a rectangular, shallow steel pool of water containing two rocks, casting strangely impressionistic reflections as you look in. Meanwhile, Beyond of Ring contrasts two 10 metre steel bars, one straight, and one a ring, inviting visitors to walk through.

The sculptures are part of the artist’s “Relatum” series, selected to sit amongst the Rijksmuseum’s gardens and inside amid the artworks, inspiring all kinds of reactions from simple fun to deeper thought.

Standing next to a steel wall between two large stones, Lee said while he is attracted to stones for their sense of universality, his work is at the end of the day about human beings: “Do you maybe remember the Berlin Wall, or what we used to term the iron curtain?” he said.  “An invisible wall exists in each society and in each self. Even with this visible wall, this stone is trying to make a dialogue. Humans try everything to make dialogue possible.”

Lee Ufan in the Rijksmuseum Gardens runs from May 28 to October 27