Cake (firework) been blown off by the discharging stars). In a traditional cake, all the candles point upwards; a variant is called the "fan" or "angle" cake. Cakes are one of the most popular types of firework, as they can create spectacular and long-lasting effects from a single ignition while minimising safety concern. In the UK, the reclassification of aerial shells to Category 4 has popularised cakes as a method for achieving similar effects while staying within safety guidelines, particularly by firing multiple candles at the same time. Cakes vary greatly in size, weight and duration. Some last only a few seconds
Fair cake-cutting or more agents assign a positive value, so all parts of the cake are divisible. Additionally, in some cases, the value functions are assumed to be sigma additive (the value of a whole is equal to the sum of the values of its parts). In the following lines we will use the following cake as an illustration. The original and most common criterion for justice is "proportionality" (PR). In a proportional cake-cutting, each person receives a piece that he values as at least 1/"n" of the value of the entire cake. In the example cake, a proportional division can be