It would be cool if you added the ability to make your own custom patterns.

I am not sure how you could do it. I don't think it would need to be user friendly. But Something for those of us that want to add something different to this plugin.

Custom patterns are possible, but only via the API. You would have to write an add-on plugin to implement a custom pattern. It would be extremely difficult to do anything user-configurable, and probably not useful for an overwhelming majority of users.

If you were interested in making a custom pattern, you would make a new plugin that depends on VeinMiner's API, create a new class that implements VeinMiningPattern, write the code to actually implement it (you could refer to other pattern implementations), and register it in the PatternRegistry when your plugin enables.