Three guns and one goes off, one's empty, one's not quick enough
One burn, one red, one green

from ∆ (Alt-J) – Tessellate Lyrics on Rap Genius

Meaning

In the love triangle, she goes off (burn) and completely burns their ties.

One’s empty (red), which is the other guy, who’s not really even in this situation (argument).

One’s not quick enough (green); he’s green with envy and he wasn’t quick enough to secure their love.

Alt-J also is describing another triangle; in this case, a Mexican standoff. This line and the next are referencing The Good, the Bad, and the Ugly, when the three characters face off in a graveyard, each hoping to search the graves to find buried treasure. After the camera spins* from face to face for several minutes, one character shoots another, who isn’t quick enough, and the third’s gun is empty.

http://www.youtube.com/watch?v=P8IwIzTlXwE

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