Cut 2 oranges and 4 lemons in half, scoop out the flesh, then put the rinds in a muffin tin to keep them level. Boil 1 1/2 cups water, add two 3-ounce boxes orange gelatin, mix and cook, stirring, 3 minutes; pour the mixture to the brim of each orange half. Repeat with two 3-ounce boxes lemon gelatin and the lemon halves. Refrigerate 3 hours and slice into wedges.
Photograph by Charles Masters