We now turn to explore CA recall. The CA remembers its previous states and can load them whenever necessary.

The CA is controlled by the following buttons:
Plant : Plants a zygote. 
Shorter: Makes CA shorter
Longer: Makes CA longer 
Count at injury (CAI)  is a set point above which injury is triggered. Here  CAI = 4;
Kill CA
Recall: The current state is replaced with state -5, which was the CA state five time units ago.
Add state: When this button is active ‘Recall’ adds state-5 to the current state.
Stop movement:  

When the experiment starts CA is isolated and does not interact with its environment. Click on ‘Kill CA’ and on ‘Recall’. The current CA state is replaced with state -5.  Now repeat clicking on ‘Recall', CA structure will change, yet when you stop bothering it the CA will regain its 46 cycle.

Click on ‘Add state’  and click once on ‘Recall’. The CA will enter a transient and remain symmetric. It will either resume its isolated state, or die. Your task is to repeat clicking until the CA hits one of the horizontal lines whereupon it starts moving upward or downward always maintaining a solution. You may click on ‘Recall’ as long as you wish, the CA will change its structure, yet when you stop clicking it will resume its typical solution.

 Zygote and stem cell

The CA will always attempt to end its perturbation and create a solution, otherwise it will die. It  may rescue itself by entering a state which consists of one cell, called here a stem cell . This states always ends in a solution. When the CA dies it plants a zygote and starts cycling again.  The number of death events is shown in the applet. You will notice that most single cell states are stem cells and occasionally zygotes, and the CA is pretty robust.

Let’s summarize the CA behavior. It starts as an isolated CA. When perturbed it will regain its initial solution. Eventually it will create a 29 state solution. In its isolated state following perturbation it remains symmetric. Once it hits one of the border lines it will start moving back and forth maintaining its typical solutions.