"31 cubes" is a second of 3 artworks, discussing the memory of matter and space. The first was executed in June 2013. I placed an unauthorized underground conceptual artwork in one of the most prominent 20th century art halls of the Israeli Museum, Jerusalem. I went into the museum undetected and when the guards looked away I place my artwork in the corner of the hall and rushed out. The artwork went un-detected for 3 weeks and then was removed from the hall. This artwork refers to the memory of the space along the time axis, based on Henri Bergson's perception of space and time. My work relates to all the artworks, curators, visitors, museum staff and the interactions that took place in this hall - past present and future.