PCB microstrip antenna
Designing (PCB) antennas is a science by itself !

The 3R rule you mention probably applies to a certain type/configuration of antennas only. The fact that there are many uniquely shaped antennas tells you that there are many different solutions.

Usually these antennas are designed by a specialist using 3D Elector-Magnetic simulators like CST or HFSS. This software + some imagination + experience + a little bit of magic can sometimes result in a usable antenna ;-)