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==Sharing Attacks==
The development has not finished. [[Lasse Hansen]] came up with another stunning idea <ref>[[Lasse Hansen|Lasse Hansen's]] [http://www.open-aurec.com/wbforum/viewtopic.php?topic_view=threads&p=185506&t=5441 postmask trick], [[Computer Chess Forums|Winboard Forum]], May 09, 2008</ref> , to use a final [[General Setwise Operations#Intersection|intersection]] by attacks [[On an empty Board|attacks on an empty board]], to share tables by two (rooks) or even four (bishops) squares. Bishop sharing is simple to understand, since there are light and dark colored bishops with disjoint attacks-sets, able to share the pre-calculated union of two square-attacks.
The trick is to share even equal colored bishops and rooks where both attack-sets are not disjoint - but all members of the intersection are always set, since they are direct neighbors of both sliders. This is how rooks and bishops may share union-attack-sets by two resp. four squares:
