Four short plays of Sam Shepard, the avant-garde playwright whose 1979 Pulitzer Prize for drama was almost as shocking as his plays to some members of the theater establishment, are being staged in a joint venture by two of Washington's adventuresome young theater companies.

The coteries of Shepard admirers feel he is speaking in modern myths and revealing deep truths for our time. There are others who find only absurdities in his dialogue, overblown verbal metaphors and an impulse to shock.

If you are curious or want to be challenged, you are taking more than a dramatic risk in attending "Sam Shepard/4 Plays" in the loft theater space at the storefront Washington Project for the Arts, 1227 G St. NW.Be forewarned that there is no air-conditioning, and although fans do help, it is wise to dress as coolly as possible.Not only language can be suffocating.

Shepard's four short plays from the early and mid-'70s are being performed in two alternating-night programs by the Independent Theatre Project and the Paradise Island Express on a Thursday-through-Sunday schedule through July 13.

Program A offers "Killer's Head," "Action" and "Cowboy Mouth." Program B repeats "Killer's Head" with a different actor taking over the single role in a separate interpretation. It is paired with "Suicide in B Flat."

Shepard's plays, with their unstructured eccentricities, non sequiturs and concentration on the irrationalities of everyday life, challenge a director to use his resourcefulness in staging. Jack Halstead and Kim Peter Kovac, two imaginative directors in experimental theater in Washington, have managed to bring some dramatic tension to the Shepard's chaotic, absurd world.

"It's hard to have a conversation," says one of the characters in "Action."

That is certainly true of most of the characters in the Shepard's plays. In "Action," it isn't easy for the two men and two women, mysteriously stranded somewhere in an isolated cabin, to carry on a conversation while smashing chairs, constantly pouring water over one hand in a pail, doing a shoft-shoe shuffle sitting down, and talking to the audience in soliloquy. Shepard can write arresting moments on the stage when he touches on alienation and loneliness. "Give me a reason for me to move," pleads Jeep when he tires of pouring water over his hand.

Both alternate-night programs open with "Killer's Head." On center stage, a blindfolded man with tattooed arms is tied in a chair. As Mazon, the man in the electric chair, Michael Henderson delivers a 12-minute, stream-of conscious monologue on horses and cars as disassociated images run through the mind of a roustabout killer before the switch is pulled for his electrocution. On the second schedule, Joe Kelley takes over the role.

"Cowboy Mouth," which is the concluding presentation of Program A brings together Halstead and Deirdre Lavrakas, who previously have worked together with considerable promise. Both again give strong performances with Halstead as Slim, a rock 'n' roll singer of modest talents who is picked up by Lavrakas' character, a strange gal seeking a rock savior. Wallace Whilhoit Jr. does a fine striptease as he emerges from a lobster man into a sexy rock singer.

Also appearing in the productions are Adrian Engel, Ceil Kovac, Lynn Brice Rooney, Jon Carlos Brocaz, and Maureen McGinnis.

It's worth taking risks in the theater, both for the theater companies and playgoers alike. While you can applaud the effort, it sometimes can be disquieting to feel that the result doesn't justify the effort. At least, Paradise Island Express/Independent Theatre Project do offer the opportunity to sample four of Shepard's short plays and find what's in them for each of us.