k3d/share/shaders/k3d_checkerboard.sl:14:  float mixamount;
k3d/share/shaders/k3d_checkerboard.sl:37:      mixamount = 0.0;
k3d/share/shaders/k3d_checkerboard.sl:41:      mixamount = 1.0;
k3d/share/shaders/k3d_checkerboard.sl:44:  checkcolor = mix(EvenColor, Cs, mixamount);
