Devices (10) comprise oblong light sources (1) that produce light for creating relatively bright zones (2) and obstacles (3) that block parts of the light for creating relatively dark zones (4). The relatively bright and relatively dark zones (2, 4) are separated by transitions (5). To soften these transitions (5), the obstacles (3) are provided with irregularities (6), such as curved edges or interruptions of straight lines of the obstacles (3) or texture. The oblong light source (1) may comprise a light unit in the form of a tube or an array of light units. The obstacle (3) may form part of a housing of the device (10). The relatively bright and relatively dark zones (2, 4) may be zones of a wall (7), a ceiling (8) or an object (9) outside the device (10) or may be zones in or at or of the device (10). The device (10) may be a video device such as a television receiver or a lighting device such as a lamp.