Sentence:  Among, ["sic"] his other achievements, Matiyasevich and his colleague Boris Stechkin also developed an interesting “visual <WSD>sieve</WSD>” for prime numbers, which effectively “crosses out” all the composite numbers, leaving only the primes. 
Meaning of the word marked with <WSD> tags:  A process, physical or abstract, that arrives at a final result by filtering out unwanted pieces of input from a larger starting set of input.