This is the 4th congressional district in Illinois. Its modern art shape is the result of a political tactic called Gerrymandering. After each census the States in the US undergo a process called redistricting where the boundaries of the electoral districts are redrawn to make sure that the populations of the various districts remain more or less equal. This process becomes gerrymandering when the new districts are drawn to give electoral advantages to one party over the other.
This is accomplished using 2 techniques: packing and cracking. Packing refers to putting as many of a group into one district to reduce their effect in other areas. The Illinios 4th (pictured above) is an example of packing as it groups 2 major concentrations of democratic leaning Hispanic voters together with a thin band. This artificially creates multiple Republican friendly districts around this heavily Democratic one. Cracking is when the districts are drawn to separate the other parties supporters into multiple districts where they are the minority and thus limit their ability to effect the vote.
The net result of these map drawing shenanigans is that not all votes count equally and the democratic process is subverted from the outset. I drew my examples from the United States where gerrymandering is rampant but it does occur in other countries as well.
If you want more information on Gerrymandering and its effects, check out the Wikipedia article for a good introductory primer, by clicking here.