Directional particle filter

DETAILED DESCRIPTION What is claimed is: 1.
A directional particle filter for selectively blocking specific particles whose projected paths intersect a predetermined point relative to the filter comprising a plurality of non-intersecting surfaces arranged in layers, each surface comprising multiple units, combinations of said units forming passing and blocking tuples, each tuple comprising one unit from each of said surfaces such that the projected path of any specific particle through the filter traverses a single tuple, all of said blocking and passing tuples being so arranged that the projected path of each specific particle through the filter that intersects said predetermined point relative to the filter traverses a blocking tuple, and the projected paths of specific particles through the filter that do not intersect said predetermined point traverse passing and blocking tuples, said units being further arranged such that no specific particle deflected by said units passes through said filter.
2.
The directional filter of claim 1, wherein said blocking tuples selectively block specific electromagnetic particles.
3.
The directional filter of claim 1, wherein said blocking tuples selectively block specific nuclear particles.
4.
The directional filter of claim 1, wherein said units are transparent or opaque units.
5.
The filter of claim 4, wherein said filter comprises three surfaces, each surface comprising a pattern of one-third opaque units and two-thirds transparent units.
6.
The filter of claim 4, wherein particles whose projected paths intersect any of two predetermined points relative to the filter are selectively blocked.
7.
The filter of claim 6, wherein said filter comprises two surfaces, said first surface comprising a pattern of one-third transparent units and two-thirds opaque units, and said second surface comprising four-ninths transparent units and five-ninths opaque units.
8.
The directional filter of claim 1, wherein said filter comprises two surfaces.
9.
The directional filter of claim 8, wherein said first surface comprises a first pattern of transparent and opaque units, and said second surface comprises a second pattern of transparent and opaque units complementary to said first pattern