Long description

Each figure consists of two sets of vertical blocks labeled disk. Each block is marked 1 and 2 respectively.

Figure a: Here the first and second block is labeled old. An arrow labeled crash is placed to the left of block 1 which points upward.

Figure b: Here the second block is labeled old, and the first block is shaded and labeled E C C error. An arrow labeled crash is placed below block 1 which points upward.

Figure c: Here the first and second block is labeled new and old respectively. An arrow labeled crash is placed between the two blocks and points upward.

Figure d: Here the first block is labeled new. The second block is shaded. An arrow labeled crash is placed below block 2 which points upward.

Figure e: Here the first and second block is labeled new. An arrow labeled crash is placed to the right of block 2 which points upward.