Here is a copy of the original alignment graph from the Advanced Dungeons & Dragons Players Handbook (yes, without an apostrophe):

(Appendix III, page 119.)

It shows the two orthogonal axes of good-evil and lawful-chaotic, and the nine regions created by the intersection of the three values along each of these axes (neutral being the middle value on both axes). The alignment graph was a handy way of visualising how actions map to the game mechanical concept of alignment.

Most players want to play good, law-abiding characters. Traditionally this can be done by keeping you actions within the blue zone and avoiding the red zone, as shown below:

Transcript

GM: Ah, Jim, Annie, you're back.
{Anakin and Padmé are hugging and kissing at the landing platform near her apartment}
R2-D2: So, you're okay with Annie playing an evil character now?
Padmé: Yeah, we decided it was lawful evil, not chaotic.
R2-D2: Okay, now we've decided to be evil, we should be able to do anything we want.
C-3PO: I'm not evil! I'm all gold and shiny!
Padmé: And I'm still not evil.
Obi-Wan: Wait, Pete, when did you decide to be evil?
{beat}
Obi-Wan: I can't believe I even said that.
Obi-Wan: So... You realise Anakin and Padmé—
Padmé: There have been good people married to evil people before. If they love each other enough they can work it out.
Obi-Wan: Um...
Padmé: Like Hitler and Eva Gabor.
R2-D2: What?
Padmé: Well she was a bit evil, but compared to Hitler...