The sunset light frames the scene that looks like a landscape at the first sight. Focusing the subject the rainbow colours create a mass that we can better define looking at the detail of the eye: it is a moving bison, whose body is composed of other forms of life. A series of fishes, one close to the other, makes the ground stepped by the bison as extreme and ideal, a bed of grass as extended as a sea, drawn by the accumulation of the animals welcomed by the sea basin. The idea of representing the bison as composed of what it feeds itself with, allows the Painter to play on the essence of life. The grass becomes a wavy land and the fishes in it create a movement extended beyond the limits of the canvas, invading the frame. The bison walking through the sea of grass points out the myth of the frontier, firmly anchored to the territory of the American steppe. As the painting doesn’t stand at the limits of the picture and the sea invades the frame, so the American nations pioneers’ walking didn’t stop in front of the loosing sight horizon, constantly looking for a frontier that could be synonymous of restart and not of arrival.