Bottlebrush Gallery & Shop, 539 Main St., Harmony,

presents "Th3 4rt 0f Numb3r5" by Baylee Kushner, who creates art using mathematic algorithms and customized color gradients. Call 724-452-0539 or visit the Web site, www.bottlebrushgallery.com

Maridon Museum, 322 N. McKean St., regularly has hundreds of pieces of ancient and contemporary Asian art as well as Meissen porcelain on display. Regular museum hours are 11 a.m. to 5 p.m. Tuesdays through Saturdays and noon to 5 p.m. Sundays; closed Mondays and holidays. Admission is $4 for adults, $3 for senior citizens and students, and free for children younger than 8; children must be accompanied by an adult. Tours are led by trained docents and are available with advance notice. The museum also has a gift shop specializing in objects relating to China and Japan. Call 724-282-0123.

<B>Andy Warhol Museum</B>, 117 Sandusky St., is exhibiting "The Vader Project," an exhibition that examines the iconic "Star Wars" villain through the eyes of 100 international pop surrealist and underground contemporary artists from around the world. The display continues through May 3. Hours are 10 a.m. to 5 p.m. Tuesdays through Sundays with extended hours until 10 p.m. Fridays; closedMondays. Admission is $15 for adults, $9 for senior citizens, and $8 for children. Call 412-237-8300 or visit the Web site, www.warhol.org.<B>Carnegie Museum of Art</B>, 4400 Forbes Ave., hosts "Opera for a Small Room," a collaboration between contemporary artists Janet Cardiff and George Bures Miller through July 19 in Heinz Gallery A. The exhibit introduces visitors to the quirky world of an imaginary man named R. Dennehy, the owner of a collection of opera records that the artists purchased at a second-hand store in a small town in British Columbia. Hours are 10 a.m. to 5 p.m. Tuesdays through Saturdays, with additional hours until 8 p.m. Thursdays, and noon to 5 p.m. Sundays. Closed major holidays. Admission, which includes the Carnegie Museum of Natural History, is $15 for adults, $12 for senior citizens, and $11 for students and children age 3 and older, and free for members and children younger than 3. Call 412-622-3131 or visit the Web site, www.cmoa.org.<B>Sweetwater Center for the Arts,</B> 200 Broad St. in Sewickley, is hosting "The Day After Tomorrow," an exhibition of contemporary ceramic sculpture, through Saturday. Gallery hours are 9 a.m. to 9 p.m. Mondays through Thursdays and 9 a.m. to 5 p.m. Fridays and Saturdays. Admission is free. Call 412-741-4405 or visit the Web site, www.sweetwaterartcenter.org.<B>Mattress Factory, </B>500 Sampsonia Way, is showing "Predrive: After Technology" through April 5. Call 412-231-3169.

<B>Hoyt Institute of Fine Arts</B>, 124 E. Leasure Ave., New Castle, presents Louis Zona lecturing on Robert Motherwell and the Abstract Expressionists at 7 p.m. tonight. Zona is the director at the Butler Institute of American Art and professor of art history at Youngstown State University. Admission is free, but seating is limited and reservations are requested. Call 724-652-2882.