Hi, Lets say I'm documenting a low-level protocol or file format and want to produce a picture such as the TCP header (etc) table (http://izecksohn.com/pedro/pub/tcp_header.jpg), what's the best program to use for that? Another example: http://www.wtcs.org/snmp4tpc/images/TCP-Header.jpg I have tried Openoffice drawing tool in Writer, and it does not align well. Inkscape might be good as I can snap to grid. I could use a spreadsheet and then export to picture. Is there a special purpose application for this that anyone has used and would reccommend? I need to be able to insert text into the cells or perhaps refer to the cells in some markup way - also the cells should be fixed width as each cell would represent one byte. Any suggestions please? How would, for example, a graphics designer go about doing this? Thanks all, Srdjan