Tuesday, September 11, is the sixth anniversary of the terrorist attacks that killed thousands of Americans. An exhibit by a new local conceptual-performance art group will mark the anniversary, and it will offer Rochesterians an opportunity to share their thoughts about the attacks.

The exhibit, "Post:September11," features more than 3000 index cards filled out by New Yorkers in the days following the attacks. Some feature messages of solidarity, others calls for revenge, other prayers for peace. They were originally collected and posted in windows alongside 42nd Street in Times Square by the art group Chashama.

One member of that group was native Rochesterian David Henderson, who is now back in Rochester and is co-founder of the new group Method Machine. The group will exhibit the cards in the windows of Rochester Contemporary (137 East Avenue), RoCo's window in the Sibley Building on Main Street, and at Conde Photography (650 South Avenue). The cards will be posted one at a time starting at 8:31 a.m. on September 11 and will continue on display through September 23.

The exhibit also has a participatory element. Index cards and markers will be available at each of the sites during specified times, and people are welcome to write their own thoughts.

Multidisciplinary, interactive art projects are what Method Machine is all about, Henderson says. The group - which he co-founded with his high school friends, Marcy J. Savastano and Michael Francis O'Connor, all now involved in the local theater community - is looking to broaden the concept of what "performance art" means.

"We're interested in doing theater that really challenges people, which isn't necessarily what people want," Henderson says. "But sometimes people don't know what they want until you give it to them."

To that end, Henderson says the group has discussed "high-concept" exhibits, large-scale works, and shows performed in nontraditional spaces. Details for Method Machine's next project have yet to be settled, but tentative plans include a staging of the Reagan-era play "This Is Our Youth" sometime this fall.

In the meantime, Henderson is hoping people will check out and contribute to the "Post:September11" exhibit. "It's an opportunity to see how another community experienced a national tragedy," he says. "We all experienced 9/11, but as the exhibit shows, each person saw it in his [or her] own way. At the same time, it goes to show you how we're all alike and all have these thoughts."