Concept of the 'area rule', reducing draft of supersonic aircrafts.
Remade to SVG by <a href="//commons.wikimedia.org/wiki/User:Petr_Dlouh%C3%BD" title="User:Petr Dlouhý">user:Petr Dlouhý</a>
<span class="int-own-work" lang="en">Own work</span>