"Fox Against the Fence," two one-act plays at the New Playwrights' Theater, reveals a distinctly novel dramatist in John Sedlak. One might call his style surrealism.

What he gives us is not what relly happens but how it seems to be happening within the mind of his protagonist. Fiving its title to the double bill, the first play presents a murder case involving a black poolhall hustler, the perplexing traditions of a white courtroom and the disappearances and reappearances of his intimates. It is as though a black, prankish Tornton Wilder were diving into Kafka territory.

This distinctive tone also runs through the second play, "Gus and Company," a fantasia on TV violence as it seems to an actor auditioning before strangers for he knows not what. As in the first play, the audience is not held at a distance from the action but instead seems to exist within the mind of the central character.

Both plays I found absorbing and amusing but I would not want my life to depend on how precisely the outline has been defined. They might be tighter but, oddly, the uncertainties or length do not nag at one. What comes through is the eerie, elusive spell of realities transformed into unrealities.

Author Sedlak is a Virginia lawyer who has worked closely with Lorton inmates. "Fox, Against the Fence" was one of last year's "reading productions" for NPT and had its first full presentation during the summer's Eugene O'Neill Playwrights' Festival.

NPT's ingenuity in furnishing these mental interiors is nicely fanciful. Within Robert Graham Small's production design, Paul Hildebrand Jr. has directed "Fox" and Small has staged "Gus." Hildebrand's challenge is especially demanding for the moods must flow with the irrationality of sliding mercury.

The casts, nine for the first, eight for the second, are assured indeed, with Richard McNair and Steve Jones outstanding in the leads. Performances at 1742 Church St. NW are Wednesdays through Sundays at 8, with reservations at 232-1122.