These are two paintings that are each other's mirror image. In the photo, they are placed against each other. It's also possible to hang both parts with an opening in between.
The design rose from a search, in the footsteps of De Stijl, for the most basic constructivist possibilities that can be derived from the square and the line.
With the theory of De Stijl, a visual language has emerged as an imaginary world sometimes containing optical illusions.