It was Supper that prompted thoughts of borders. . . . Inside are long folding tables, which soon become the site of a Last Supper, arranged like Leonardo da Vinci’s, the kind of farewell dinner that precedes leaving one’s homeland. The tables are key. On four legs or tilted, they serve as platforms for the dancers, who scramble up their sides or run along their edges. The tables represent walls, as at borders, and the dancers slip through the gaps between them, gaps that sometimes slam shut. . . . Directed and choreographed by Silvana Cardell, who herself emigrated to Philadelphia from Buenos Aires more than a decade ago, “Supper” is a collection of imagistic sketches. It’s most effective when it’s moving fast, conveying the terror and difficulty of many emigrant experiences.