As you can see from the screen shot, the pattern fill menu allows you to choose between two color, full color or bitmap.
A two-color pattern gives you just that -- the choice of two spot colors in a high contrast pattern: checkerboard, spots, stripes, stars and other common shapes. Both the two color and the full color patterns in this menu consists of vector graphics made of lines and fills that stay smooth when they are resized. The third choice is bitmaps, the format used for photographs and scans, consisting of dots of color which lose their resolution the bigger they are sized
For the fills in my example, I chose four-color patterns. I looked for patterns that had square components or small elements that would not show a noticeable line when joined together. I also set my pattern size the same width and height of my box. When they are not the same size, this is what you get (see image below).
In the sample of the duplicated stained glass tiles, it is obvious the tile is not seamless; you can tell where one tile ends and the other begins. Sometimes, making tiles seamless is a lot like adjusting your pattern up, down or over while wallpapering a room. In this case, however, we will not be adjusting the second tile, but adjusting the first.
If you break this image down to its smallest component, you will see a tile that looks like the one on the left, the same image Corel Draw displays as the choice for this pattern in the fill menu. (See screen shot above). Studying the way Corel Draw sets up these samples or repeating tiles can give you ideas about how to draw or sample your own creations. Just keep in mind how that tile is going to repeat and break the elements of the pattern down to its smallest component. For example, look at the tile Corel displays as a choice for spots: