More people probably now know the term "seamless tile" than ever before because they have seen them used as back grounds on web pages. But seamless tiles are nothing new--you just know them as wallpaper, rugs, fabric, wrapping paper and a host of other uses.
A seamless tile is design that, when repeated or tiled, does not show seam lines where the tiles join together. Any part of the design that touches the edge of the tile must match exactly to the edge of the tile that joins it.
On the computer
This can be done easily with computer programs like Corel's Photopaint or Fractal Design's Painter or any other program that lets you "offset" the edges of the tile.
In Painter you create a seamless tile by selecting an area, then Patter xxxx. Then when you draw in the image, any line that goes off the edge, comes back on to the opposite side, making a perfect match.
Since Photopaint, with the Effects; @d;Offset command. uses a very different procedure (much akin to the traditional paper method detailed below). The edges of the image are brought to the center, where you can paint across them to makea match. The new outer edges were originally joined--so of course they will match when tiled.
It can also be done with a simple graphics program thet lets you cut part of an image and then pste it into a new position. I have included these doirections, using Window's Paint.