In a cramped studio in Ravenna, Italy, Takako Hirai runs her finger along the cracks in a mosaic artwork depicting dappled light in a park. The spaces between the tiles, she explains, determine the flow and movement of a mosaic, even more than the arrangement of the pieces themselves — as if meaning were slipping through the cracks to be teased out by the observer. It makes mosaic the perfect medium for embedding the kakushi-e, or hidden images, that the artist from Kumamoto places in her work — both to hide her inner self and reveal it.