Sometimes it happens that the only way in which a cell can be illuminated is to place a lamp into that cell. The highlighted cell shown
here is such a cell. It is shielded from other cells in the same column by the two pattern cells. Other cells in the same row are shielded from
it by pattern cells, or are already designated as either Illuminated or Prohibited.
The highlighted cell is referred to quite appropriately as an
Orphan Cell, and there is no option but to fill it with a lamp.