The mayan pictoglyphs or alphabet in images makes for some interesting thoughts, especially when the most common characters (and also in this case a single digit numeral (4) and involve such an act that we rarely like to contemplate.  I was thinking of the word sacrifice, the act of sacrifice, and it is uncomfortable to put it mildly.  I wonder whether these ancient rituals were actually sacrifices (which implies that its a volitional and unselfish act on the part of the individual from which life is taken) or whether it was more like murder, where life is taken by force.  Either way it is still worrisome. But, that said to clear my "head" these are fantastic glyphs, so complete, contained, smooth, and beautiful.  I could imagine in this image the altar (brown posts) the river of live giving blood (red) the tiny heart in the blip below the altar, the mountains (green) sky (blues).