Catherine's Jello Ribbon Salad

2 (3 oz.) pkgs. strawberry jello
1 (3 oz.) pkg. lime jello
1 (3 oz.) pkg. orange jello
1 (3 oz.) pkg. lemon jello
2 cups milk
1 cup sugar
2 envelopes plain gelatin
1 pint sour cream
2 tsp. vanilla extract

In separate bowls, dissolve packages of jello in 1 cup boiling water each. Add 1/2 cup cold water to each. In saucepan bring to boil 2 cups milk and 1 cup sugar. Soften plain gelatin in 1/2 cup cold water; add to milk mixture. COOL TO LUKEWARM, then add sour cream and vanilla. Set aside. Pour prepared mixture of one package of strawberry jello into a lightly oiled 9 x 13-inch clear glass pan. Refrigerate until set (about 20-30 minutes). Put layer of milk mixture (about 1 cup) on top of red jello - pour some on top and tip dish to spread. Should be a thin layer. Refrigerate another 20-30 minutes. Continue with other colors as layers set, using milk mixture between each, and ending with the second red layer. Cut in squares to serve.

Notes: Flavors and colors can be mixed as desired, as long as you have 5 total jello packages being used. Examples: red, white, and blue for 4th of July; red, white, and green for Christmas; or red, orange, yellow, and white for Thanksgiving.

Also, I seem to remember that sometimes, towards the final layers, the (unused) milk mixture starts to thicken and set. If this happens, you can microwave it for a few seconds and stir until smooth again.