Pilobolus began as an experimental troupe of Dartmouth College dance students who combined collaborative choreographic processes with a unique weight-sharing approach to partnering. Thirty-three years later, the ad hoc dance collective has matured into a successful, self-sufficient arts organization, and the seven-person touring Pilobolus Dance Theatre makes its fourth Ruth Eckerd Hall stop this weekend. Audiences can expect impossible feats of weight-balancing and difficult, sometimes humorous contortions in a program of original works that includes Aquatica, a meditative piece that takes place in the oceanic underworld; Day Two, a classic Pilobolus work about the second day of creation set to music by Brian Eno and the Talking Heads; and a new, untitled duet. Sat., Jan. 21, 8 p.m., Ruth Eckerd Hall, 1111 McMullen Booth Road, Clearwater, $37 and $42, 727-791-7400, www.rutheckerdhall.com.