Currently NuBot puts all the available liquidity in a vertical wall, according to the initial design outlined in the whitepaper. The above model worked out to well to prove Nu’s capabilities of pegging, but now it is time to move forward.

Many new hypothesis emerged around the next direction, and here I am, trying to make a synthesis and put them together into something more concrete. If you haven’t done yet, I invite you to read past (long) discussions : one - two - three .

## The option that I personally prefer, is to use a parametric model to distribute the liquidity offered by the custodian around the center price of 1$.

This afternoon I prepared a proof of concept parametric model to help the discussion and gather ideas.

- The model can be configured by the custodian using the configuration file.
- The model is dynamic, in the sense that its parameters can be manipulated at runtime.
- I imagine NuBot capabilities to autonomous adapt parameters to best fit market conditions.
- The buy and sell liquidity can be modelled separately

The image below is a graphical representation of the model proposed.

```
Parameter,Description ,Accepted values
offset, distance from 1$ target price, USD
wallHeight, amount of base-liquidity available at the best price, USD
wallWidth, total width of the order book, USD
curve:type, type of model, lin-log-exp
curve:steepness, steepness of the curve, low-mid-high
density, distance between orders , USD
```

Below, a sample JSON representation of the model, to add to custodian configuration file.

```
{"options":
{
"sellSideLiquidityModel": {
"offset" : 0.1 ,
"wallHeight" : 200 ,
"wallWidth" : 0.5,
"curve" : {
"type" : "log",
"steepness" : "mid"
},
"grain" : 0.02
},
"buySideLiquidityModel": {
"offset" : 0.1 ,
"wallHeight" : 350,
"wallWidth" : 0.3,
"curve" : {
"type" : "exp",
"steepness" : "high"
},
"density" : 0.02
}
}
}
```

The model is simple and at the same time flexible enough for making it fit in different market scenarios. It is a first step toward the future direction.

I would love to gather inputs from the wise community and bring the discussion forward.

EDIT: ideally NuBot should be able to read the existing order book and adapt the offer to it, such that the resulting order book is as similar to the ideal shape as possible.