I’m afraid I’ve lost track of the source of this here information. I suppose the colors could be read as indicating whether to “go” or “use caution” or “stop” or whatever. (Click the chart to enlarge.) The color-coding indicates whether a hand is ranked in the top 25% (green), the second 25% (yellow), the next 25% (red), or the bottom 25% (black). The chart at the left is a fairly useless, though somewhat interesting piece of trivia I picked up some time ago that ranks all 169 starting hands in hold ’em.