1. An apparatus for manipulating a two-dimensional array of Boolean coded points, comprising: memory means (15) for storing the array, said means including means (83, 85, 87) for selectively addressing linear subarrays in one of two directions and at an arbitrary starting address along either of the array dimensions; means (17, 11, 13, 21, 19) for extracting the selectively addressed sequences from the memory and for replacing information at the same or other selectively addressed locations in the memory at a continuous rate; a source (1) of Boolean coded information; means (3, 6, 11, 17) for logically combining in serial fashion the linear subarrays extracted from the memory means with serial information from the source; and control means (21, 23, 25, 19, 27, 29) for specifying the logical function performed by the combining means and for designating the addresses both for extracting data from the memory and for writing the logically combined sequences into the memory.