This is my attempt to explain just how Biots works using pretty pictures I made in Paint.
Each Biot has its own tiny program, called a memome. Each memome is made up of several memes. These memes can be thought of as condition/action pairs. Conceptually They look like this:
The biots are essentially stimulus-response machines. When a certain condition is met, the biot will respond with the corresponding action in its memome. In these tables, the blue arrows indicate a success, meaning either the condition preceding it has been met, or the action preceding it it possible. The red arrows indicate a failure, meaning either the above condition was not met, or the above action is impossible for the biot to perform at the moment. Examples of actions that may fail are reproduction, which requires the would-be parent to have enough energy to reproduce, and movement, which can be blocked by obsticles such as rocks.
The memes are linked together to create memomes of varying lengths, the red failure arrows coming from the above meme's condition and action nodes are both linked to the next meme's condition node. Each turn, the biot seaches its memome-program to come up with what action it should take. It starts with its first condition and follows the arrows through the memeome. If a condition is met, it evaluates the corresponding action to see if it is possible. If the condition is not met, it looks to the next condition. If the action is possible, it executes that action and the memome has done its job for this turn. But if the action is not currently possible it goes and looks at the next meme's condition and so on, until it does find an executable action. If no conditions are met or no actions are possible, the biot has a default action, which is to give up and take a nap. The memome, made up of linked memes, looks like this:
There are two special conditions, one that always succedes and one that never does. Always is useful for actions like reproduction and eating, which should always be attempted. Never is just useful for storing an unused action that may have an effect on some later descendant after a mutation.
The actions that turn left and right are special in that they never fail. Nothing can prevent a biot from turning if it wants to. Pass is a special action that always fails. Like never, it just exists to change some later descendant.
Below is an example of what a memome might look like.
Let's pretend that the biot is one step away and one step to the right of some delicious food.
Each turn, the biot looks through its memome-program to decide on an action. The first thing this biot does is evaluate the always condition. The always condition is always true, so it follows the blue arrow right to the Reproduce Asexually action. It turns out our biot doesn't have enough energy to reproduce asexually at the moment, so that action fails. Next on the list, the biot evaluates the Feel Fruit condition. Nope it doesn't feel any fruit at the moment, so on to the next condition. The next condition is another Feel Fruit, we can just skip that one and move on. Finally we arrive on the condition Not Feel Fruit which is true whenever the biot doesn't feel a fruit, we know that we don't feel a fruit, so we can evaluate the corresponding action. The action next to Not Feel Fruit is Move. Move is possible as long as nothing is blocking the biot. The biot's path is clear so it stops evaluating its program and moves one space forward, putting it just to the right of the apple.
Using the same process, in next step, the biot will turn left. The biot will continue to turn left until it ends up facing the food, because none of the circumstances have changed from the last turn. Finally, the biot is able to eat fruit because the fruit is within reach of its mouth. Let's say that this gives the biot enough energy to reproduce asexually, then the biots program will tell it to do.