Bubbles form from the agitation. A 1mm wire slices through leaving a trail of bubbles. Whisking at an increasing vigor sugar is added to sweeten the foam. How is this foam created? The molecular bonds of the protein molecular stretch trapping a layer of air making bubbles. These bubbles form the foam. Egg white whisk to stiff peaks that is the consistency you are looking for.
Like a city, foam is made from many small parts: people (bubbles) and only when the people gather it is the identity of the city(foam shape). The constant influx determines the cities growth (whisking) and the strength of the city is determined from the connection of the people (sugar).
Cities are constantly expanding and its citizen (whisk) influence the elasticity of it shape. Vigorous agitation to the people makes the people (foam) stiff. Only the perfect amount of whisking will allow the foam to grow and adapt to the future changes.