Wilson's decade-by-decade history of the Hill District during the 20th century is almost done; he still has to write installment No. 10, set in the '90s. The plays come out of Wilson in no particular order -- last year's Gem of the World was set in 1904 -- and director Stanley E. Williams has been diligent about bringing each one to town as soon as he can get the rights. The project is unprecedented, and I'm sure the full cycle will amount to more than the sum of its parts. But so far each play has a similar flaw: Wilson writes rounded, moving characters, but dissipates their drama with concepts borrowed from Shakespeare and the Greeks, as if he doesn't trust his own legacy.