Syria's civil war started out simply: local rebels fighting Bashar al-Assad's government for control of the country. But over the past five years, the war has gotten unbelievably complicated, with all sorts of different actors — including Iran, ISIS, al-Qaeda, and Kurdish fighters — joining the fight.

The following chart, from Middle East Institute fellow Charles Lister, shows just how complex things have gotten, with arrows pointing from a party to everyone it is currently fighting. The chart is perhaps the simplest depiction of the different sides I've ever seen, yet it is incredibly complicated:

This *simple* chart shows all states of hostility currently being played out on #Syria’s territory#IntractableWar pic.twitter.com/1inprNB6U0 — Charles Lister (@Charles_Lister) February 13, 2016

Perhaps the most useful thing in the chart is that it goes beyond the obvious stuff — Syrian rebels don't like Assad or ISIS, Iran and Russia are supporting the government — to get at the more obscure, yet very important, subconflicts. A few examples:

The Kurds are taking territory from some US-backed Arab Syrian rebels. This presses the Syrian rebels on another front, helping Assad shore up his position. Moreover, it screws up America's strategy against ISIS: The US needs both rebels and Kurds to take out ISIS, but they're at each other's throats.

The Turks, America's treaty allies, are also fighting the Kurds, whom they see as allies of Kurdish nationalist militants inside Turkey itself. This severely complicates America's war against ISIS in Syria's north, forcing the US to have to temper its support for the Kurdish campaign against ISIS lest it freak out Turkey too much.

Iraqi Shia militias, backed by Iran yet critical to the fight against ISIS inside Iraq, are attacking Syrian rebels at Iran's behest. This shows that the connections between Iraq and Syria don't stop with ISIS; growing militia strength in Iraq could potentially affect the Syrian conflict as well.

ISIS is the only combatant that is fighting literally everyone. The only belligerent in Syria that hasn't attacked the group is Israel, which only strikes in Syria very rarely. ISIS simply doesn't have the money or the troops to take on this many enemies at once, which explains why it's lost about 20 percent of its peak Syrian territory.

The bottom line is that everybody is fighting for their own reasons. The regime and the rebels want to destroy each other; Iran and Saudi Arabia want to limit each other's influence in the country; the Kurds want to carve out their own independent state, which Turkey strongly opposes; Russia wants to preserve its naval base in Tartus and support its ally; the US mostly just wants to destroy ISIS, but nobody else is really prioritizing that.

Which is why Lister's hashtag for the chart, #IntractableWar, is so apropos. Given all these different agendas, negotiating peace among all of the relevant sides (many of which deeply hate each other) is an extraordinarily difficult task. And since no one side is likely to be wiped out by force alone, except for possibly ISIS, it's hard to see any way this conflict will end anytime soon.