The challenge for Van der Wijk lies in creating exactly the kind of movement that evokes interaction between viewer and sculpture. Take his bronze sculpture ‘Hug’ where, in one position, two pyramid shapes depict attraction and, in the other, the intimacy of an embrace. “At an exhibition in Leiden I was told how impressive it was that such cold and heavy material radiates so much fragility and warmth. This is what I’m after,” he says. When he has an idea for a sculpture, he combs scientific literature for mechanisms he might apply, and he phones other scientists. Science and art often reinforce each other. “Sometimes, as a scientist, I stumble upon a mechanism that perfectly fits an idea, but similarly it happens that I publish articles based on applications from my art.” For example, he published about the artwork the Taaie Tiller (tough lifter) in Constructeur magazine. For this ‘Sisyphus Machine’, which lifts a rock from the water then drops it again and so on for all eternity, Van der Wijk discovered how to bypass the dead points of the four-bar mechanism.