1.Preheat oven to 180°C (160°C fan-forced). Grease and line a deep 19cm-square cake pan, extending paper 5cm over sides.
2.Make cake according to directions on packets. Spread mixture into pan and bake about 50 minutes. Stand cake in pan 5 minutes; turn, top-side up, onto wire rack to cool.
3.Level top of cake; cut cake into nine cubes.
4.Divide fluffy frosting into four small bowls. Leave one bowl plain and tint each remaining bowl with one of the suggested colours: pink, yellow and green. Spread frosting over the top and sides of cubes.
5.Cut sour straps into thin strips. Use to outline the sides of each cube.
6.Using picture as a guide, decorate cubes with butterflies, numbers and boats made from assorted lollies.
7.Using a large palette knife, or egg slide, position and stack cubes on the prepared 35cm x 45cm cake board.
8.In a small saucepan, combine sugar and water; stir with a wooden spoon over high heat, without boiling, until sugar dissolves. Boil, uncovered, without stirring, about 3 to 5 minutes or until syrup is slightly thick. If a candy thermometer is available, the syrup will be ready when it reaches 114°C.
9.Meanwhile, in a small bowl, beat egg whites with electric mixer until stiff; keep beating (or whites will deflate) until syrup reaches the correct temperature.
10.When syrup is ready, allow bubbles to subside then pour a very thin stream onto the egg whites with mixer operating on medium speed. If syrup is added too quickly to the egg whites, frosting will not thicken. Continue beating and adding syrup until all syrup is used. Continue to beat until frosting stands in stiff peaks (frosting should be barely warm by this stage).
To get the best-shaped blocks, refrigerate or partly freeze the cake, then cut the cake into neat cubes.Note