Since Stacky.program() just makes a function(x,y) I added a palette generator. red is at y==0 green y=0.5 blue at y=1.0 so the palette program "x" generates

Since Stacky.program() just makes a function(x,y) I added a palette generator. red is at y==0 green y=0.5 blue at y=1.0 so the palette program "x" generates a greyscale. "xy*" makes it orangy.