Description of the illustration cncpt294.eps

The graphic is divided into two boxes with dotted borders, one on top of the other. The top is labeled "Branch Blocks" and the lower "Leaf Blocks." The graphic contains a tree of boxes. At the top is a box with the following values: 0-40, 41-90, and so on. Three arrows point to a second row of branch blocks. One block in this row has values 0-10, 11-10, and so on. An adjacent block has values 41-48, 49-53, and so on. The last black has values 200-209, 210-220, and so on.

The leftmost and rightmost blocks each has a pair of arrows pointing down. The leftmost arrow points to a leaf block containing the following values: 0,rowid, 0,rowid, 1,rowid, and so on. The block to the right contains the following values: 11,rowid, 12,rowid, and so on. The next block contains 22,rowid and 23, rowid. Each of these three blocks is shaded. The shaded blocks are separated from the blocks to the right by three ellipses.

The next block contains values: 221,rowid, 222,rowid, and so on. The rightmost block contains the following values: 246,rowid, 248,rowid, and so on. Except for the leftmost and rightmost block, each leaf block in the bottom row is linked by a double-headed arrow to the block on either side.