Blend oat flakes with banana, water (or a clear fruit juice like, apple juice), orange juice and cinnamon. You can add some sweetener and ice cubes at this point. Divide the mixture in three equal parts.

Add kiwi and avocado to the first part and blend until smooth. Pour into a serving glass.

Combine mango with the second part, blend and pour into the glass over kiwi mixture.

Blend red berries with the third part and pour on top of mango mixture. Serve immediately.