Instructions:

Creamy Knox Blox

3 small boxes gelatin (same flavor)
4 envelopes Knox gelatin
3 cups boiling water
1/2 pint heavy cream

Combine gelatin and Knox gelatin in bowl. Dissolve in hot water. Add heavy cream and stir until well mixed. Pour into a shallow 13 x 9-inch pan. Place into refrigerator to set. Cut into cubes.