Prepare one box of green Jell-O according to package directions. Pour into pan.
Place in refrigerator for 3 hours.
In a bowl combine 1 pkg gelatin and 1/2 pkg green Jell-O into 1 can of sweetened condensed milk. Boil one cup of water and slowly add the water to the milk mixture. ** You must add this water slowly and stir constantly to avoid curdling.
Pour over set green Jell-O layer.
Repeat with the yellow jell-o layers and be sure to make sure each layer is set before pouring the other layer on top.