Code:
/mob/Login()
..()
test()
/mob/proc/test()
var/icon/I = icon('icon.dmi', "state")
I.MapColors(0,0,0, 0,0,0, 0,0,0) //okay
I.MapColors(0,0,0,1, 0,0,0,1, 0,0,0,1, 0,0,0,1, 0,0,0,0) //okay
I.MapColors(0,0,0,1, 0,0,0,1, 0,0,0,1, 0,0,0,1) //runtime error: list index out of bounds