Place dark and white chocolate in seperate bowls and melt seperately until smooth. Pour dark chocolate onto wax paper, forming 3 thick strips, leaving about 1 inch between each. Pour melted white chocolate into the empty spaces. Spread strips out so that they touch. Draw a knife back and forth across the strips to create a marbled effect. Sprinkle with candy canes. Refrigerate until hardened, about an hour. Break into pieces. Store in an air tight container for 1 week at room temperature.