"The Wall" is more of a concept than an actual oiling pattern.  It just means that the lanes are conditioned so as to correct for errant shots.  Basically, it's a lot of oil in the middle, usually between 10 left and 10 right, with much less oil outside of 10.

If done correctly, the oil pattern funnels balls to the pocket.  From what I've seen, most people, even high-average bowlers, have no idea that their apparent proficiency is an illusion served up by the easy house shot.
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seadrive
Cogito ergo bowl