k3d/share/shaders/k3d_checkerboard.sl:13:  float filterwidths, filterwidtht;
k3d/share/shaders/k3d_checkerboard.sl:22:	filterwidths = SFILTERWIDTH * TileS;
k3d/share/shaders/k3d_checkerboard.sl:25:	filters = filteredpulse(1.0 - filterwidths, 1.0 + filterwidths, filters, filterwidths);
