Shape: positive and negative: positive shape is the totality of the mass lying between its contours; in three-dimensional work, the visible shape or outer limit of a form changes as the viewer's position is changed. These outer limits are seen as shapes moving back and forth between major contours. Negative space is empty space defined by positive shape. Sometimes referred to as occupied and unoccupied space.
close up of mosiac window using colored broken glass and adhered using a silicone base clear gel. This particular adhesive is waterproof, so can hang it outside in garden. It would only cost a few dollars..