Principle of REVERSE DOWNTIME. Without this rule to reduce the compression of input-output modules, addresses can move from one line to another line closer to the input line. (a) The Activity Register is shown here with only four elements (for simplicity) and initially has addresses of certain elements (red) in a successful output line; these addresses can become displaced towards the input line. (b) The results of 20000 timesteps without REVERSE DOWNTIME. (c) Implementing REVERSE DOWNTIME during the loading of a NewLine requires the Next field of 13 to be consulted; this shows that 7 and 38 often follow 13, so, to avoid compression by 7 and 38 being loaded into the NewLine, the NowScore register for 7 and 38 is set to zero.