The stickers on the cube show the RGB color model as mapped onto a cube. Red colors are displayed on the first horizontal x-axis with coded values increasing from left to right. Blue colors are displayed on the second horizontal y-axis with coded values increasing from back to front. Green colors are displayed on the vertical z-axis with coded values increasing from bottom to top. The black color origin is located on the backside of the cube, at the intersection of faces B (Back), D (Down) and L (Left).