Combine eggs and oil, beat until foamy. Add sugar, beat until light colored and thick. Combine dry ingredients, stir into batter. Add vanilla, nuts and rhubarb by hand. Pour into 9 x 13 inch greased pan. Top with- 2/3 cup oats, 2/3 cup brown sugar,
1/3 cup chopped nuts, 1/4 cup melted margarine, 1/2 tsp. cinnamon.