Categories are funny. Ask 10 people what the difference is between contemporary ballet and contemporary dance, or how those are different from traditional ballet or modern, post-modern or post-post-modern dance, and you'll get 10 different answers. James Sewell Ballet's "Ballet Works" program has for the past 20 years taken on this very dilemma, poking and prodding at the boundaries of contemporary ballet and dance.

Friday's opening night had a relaxed atmosphere, with some of the choreographers speaking about their process. In his brief remarks, James Sewell introduced the evening by saying "Ballet Works" is a chance for the choreographers to "take a risk and try something they haven't before."

Of the four dances, New York-based choreographer Joanna Kotze's "The Rest of Everything" takes the largest leap into the form of ballet, breaking it open for a look. The dance takes the ballet vernacular and tweaks it. The dancers, wearing fluorescent aerobics outfits, wear pointe shoes, but often have their planted leg bent, disrupting the ballet lines. At another point, one of ballet's most famous warm-up routines, the flat back, which looks like a tabletop with the dancer's back perpendicular to the ground, gets morphed in Kotze's interpretation, with the dancer doing it while on pointe, tiptoeing across the stage like a strange insect.

In contrast, Amy Earnest and Lance Hardin's "Fractured," set to music by Philip Glass, looks more like contemporary dance than contemporary ballet. The weight of the performers, the way they seem to melt into each other and their undulating torsos all push the dance toward a contemporary dance aesthetic. However you define its genre, the piece remains a little too safe. While the dancers are lovely, the choreography gets upstaged by Glass' complex and riveting music.

In "Suspicious Fisherman," Houston-based choreographer Jane Weiner pushes ballet toward vaudevillian slapstick. Dressed as a fisherman, soloist Shohei Iwahama searches through a seemingly endless supply of eyeglasses before he finds the right pair. He bonks his head on the floor and eats worms. The routine is performed eloquently with long lines, turned out hips and other ballet signifiers, but somehow the work gets caught in the middle between ballet and Charlie Chaplin. Slapstick is grounded, relaxed, the opposite of ballet, so the two forms were working against each other. Both choreographer and dancer seemed more comfortable on the ballet end of things, which stops the piece short of truly embracing the physical comedy. A few more sound effects and pratfalls might have done the trick.

Finishing off the evening is Nic Lincoln's ambitious "Tart," an exploration of gender tropes and behaviors. Lincoln finds innovative ways to use the Tek Box space, such as opening up the curtains and having the dancers perform on the sill of a window located at the back wall. Lincoln seems to understand intimately how to best utilize the skills of the dancers. You might not call it ballet, but it doesn't really matter.

Sheila Regan writes about dance.