EDIT: Somebody has pointed out that these images may be violating PTI's copyright. I made these grids with dots and dashes. However, even though they're not identical to PTI's stamps, I decided it's safer to remove these links. I don't want to be accused of copyright violation. Thanks for understanding. To make up for this gaffe, I will be offering other downloads that are not stepping into anybody's copyright in the future, so stay tuned.