This patch shows four objects that are useful for generating numbers, each with a different behavior. The arguments to these objects determine how many different possible numbers the object will generate, and the range of those numbers. The range can be changed, though, by scaling (multiplying) them and/or by offsetting (adding something to) them.
In large and complex patches that have many pattr objects, it might be useful to be able to communicate with all of them at one central location. That is the purpose of the pattrhub object. With pattrhub you can alter the contents of any pattr just by using the name of the pattr followed by the data you want to put in it.
If you want two user interface objects (UI) always to display the same information, it might seem sensible to connect the outlet of one to the inlet of the other and vice versa. However, that will lead to an infinite loop unless you do something to stop one of them from always sending out the value. The set message is useful in that regard, because it allows you to set the contents (and the display) of a UI object without causing that object to send out a message of its own. The top part of the patch demonstrates this technique.
The pattr object and its related objects such as pattrhub, pattrforward, autopattr, and pattrstorage make it possible for you to store data (or any sort of message, really), recall that data when the patch is reopened, store and recall it from other parts of the patch, and make transitions from one set of stored data to another.
The matrix~ object is a multichannel audio mixer. It’s useful as a mixer of sounds, and also as an audio switcher/router, because you can route any input to any output, with built-in interpolation for smooth, click-free amplitude changes.