Put 1/4 pound each of white, blue, purple and pink candy melts in separate bowls. Melt in the microwave, stirring, until smooth. Stir a little white into each of the other colors to lighten them. Working quickly, spoon dollops of the different colors onto a parchment-lined baking sheet in a mosaic pattern, then drag a rubber spatula through the colors to swirl. Spread to about 1/4 inch thick and top with assorted sprinkles and/or edible glitter. Refrigerate until set, at least 30 minutes. Break into pieces.