Decoder for reconstructing a sample array from a data stream, configured to derive a bi-partition of a predetermined block of the sample array into first and second partitions by determining a measure for a central tendency of reconstructed sample values of a reference block of the picture, co-located to the predetermined block, segmenting the reference block by comparing each reconstructed sample value of the reference block with a threshold globally defined for the reconstructed sample values of the reference block and depending on the measure for the central tendency to obtain a bi-segmentation of the reference block into first and predetermined partitions, and spatially transfering the bi-segmentation of the reference block of the picture onto the predetermined block of the depth/disparity map so as to obtain the first and second partitions, or generating, for each of a plurality of block sizes, an ordered list of wedglet patterns, each wedgelet pattern corresponding to a combination of start and end points of a wedglet separation line, by using an algorithm determining which samples to plot to form a close approximation to a straight line between the start and end points and indexing a wedgelet pattern within a list of wedgelet patterns generated for a block size of the predetermined block using an index explicitly signaled in the data stream so as to obtain the first and second partitions; associate each of neighboring samples of the sample array, adjoining to the predetermined block, with a respective one of the first and second partitions so that each neighboring sample adjoins the partition with which same is associated; predict the predetermined block by assigning a mean value of values of the neighboring samples associated with the first partition to samples of the sample array positioned within the first partition and/or a mean value of values of the neighboring samples associated with the second partition to samples of the sample array positioned within the second partition. determining a measure for a central tendency of reconstructed sample values of a reference block of the picture, co-located to the predetermined block, segmenting the reference block by comparing each reconstructed sample value of the reference block with a threshold globally defined for the reconstructed sample values of the reference block and depending on the measure for the central tendency to obtain a bi-segmentation of the reference block into first and predetermined partitions, and spatially transfering the bi-segmentation of the reference block of the picture onto the predetermined block of the depth/disparity map so as to obtain the first and second partitions, or generating, for each of a plurality of block sizes, an ordered list of wedglet patterns, each wedgelet pattern corresponding to a combination of start and end points of a wedglet separation line, by using an algorithm determining which samples to plot to form a close approximation to a straight line between the start and end points and indexing a wedgelet pattern within a list of wedgelet patterns generated for a block size of the predetermined block using an index explicitly signaled in the data stream so as to obtain the first and second partitions;