k3d/share/shaders/k3d_oakplank.sl:132:  float inplank = plankpattern(ss, tt, dss, dtt, plankwidth, planklength,
k3d/share/shaders/k3d_oakplank.sl:148:  Cwood = mix(Cgroove, Cwood, inplank);
k3d/share/shaders/k3d_oakplank.sl:167:  float specadjusted = 1 + .3 * wood - 0.8 * (1 - inplank);
