In Rich O'Meara's "Puzzle Piece" for three marimbas, the rhythms are intricate, interlocked and constantly shifting. Opening last night's concert by Amaranth at the Universalist National Memorial Church on 16th Street NW, it made a fine introduction to an imaginative evening.

Like the other members of Amaranth (percussionist Richard McCandless, pianist Jutta Philippi Eigen and flutist Jan Pompilo), O'Meara is a performer (on percussion) as well as a composer. Amaranth's music is skilled, imaginative, often witty and never inclined to take itself too seriously. This program will be repeated Sunday evening and deserves attention.

Preston Trombly's Duo for Flute and Percussion makes some cogent statements but takes a bit longer than seems necessary.

John Cage's "prepared piano" is transformed into a one-person, keyboard-operated percussion ensemble by the insertion of weather-stripping, bamboo, nuts, bolts and washers into some of the strings. Eigen's brilliant account was followed immediately by her own "Minus 25," a complementary statement that uses the untampered strings (in dialogue with a vibraphone) to produce music of gentle, wistful lyricism.

It was beautiful -- a word that may be coming back into vogue for contemporary music. So was Pompilo's "Egeria," a haunting, melodic and intensely dramatic string quartet inspired by the Roman legend of the love between the wood nymph Egeria and King Numa Pompilius.

In "Air Rind" (like "Egeria," a Pompilo work in its first performance), spoken words become music, sometimes as pure sound and sometimes through their semantic overtones. Whether the juxtaposition was intentional or not, there is a fine balance and contrast between "Air Rind," in which words become music, and "Egeria," in which instrumental music strains at the limitations of wordlessness.