Complex sentence: Museum Boijmans Van Beuningen in Rotterdam bought the concept in 2010 and installed it in 2011; at least three visitors accidentally walked onto the 4 by 12 meter floor, and were held responsible for the damage.
Split into simpler sentences: Museum Boijmans Van Beuningen in Rotterdam bought the concept in 2010 and installed it in 2011. At least three visitors accidentally walked onto the floor, and were held responsible for the damage.