It's a joint of tubes. You start by teaching angles an acute angle, a right angle, an obtuse angle, a straight angle.

And what that is is I imagine explaining a work of art to my grandmother in five minutes, and if I can't explain it in five minutes, then it's too obtuse or esoteric and it hasn't been refined enough yet.

With few notable exceptions, such as US Ambassador to Brazil Tom Shannon, US diplomacy has lacked a strategic vision for Latin America. Barack Obama s 2008 election created high expectations in this region, too but his administration s approach has been reserved, at best, and often obtuse.