One well established kiln-formed glass technique is the pattern bar.
In most cases, the artist starts with strips of equal length glass in different colors. The strips are laid up -- or "bundled" -- to form a single block of glass. This bundle is placed in the kiln and surrounded by damns (or other support) so that the glass cannot flow when it reaches fusing temperatures. The glass is then fired so that the strips fuse into a single block of glass.
This block is referred to as a pattern bar because a single pattern runs through the length of the glass. When the bar is sliced with a saw (tile saws are popular for this) each "tile" has the same patter. These tiles are then used as design components in the final fused or blown glass piece.
This bundle is placed in the kiln and surrounded by damns (or other support) so that the glass cannot flow when it reaches fusing temperatures. The glass is then fired so that the strips fuse into a single block of glass.