How to do something like this...
A great thing about Reason is that it allows you to wire a continuous input (like a CV, MIDI CC#, Mod wheel etc) to pattern changes on something like the Matrix sequencer or Redrum. You can't do this directly (there is no pattern change CV input) but you can do it via the "programmer" in the combinator. This is a great thing to experiment with...especially if the patterns are different beat lengths/step values and you layer a few of them . In one of my other clips I used MIDI CC# signals generated by a Lavalamp to randomly switch patterns on a set of Redrum modules.
In the above above clip I have 3 matrix sequences driving each other, which can result in some random sounding patterns which repeat over long periods and can descend into chaos with one small tweak.. eventually arriving at a new repeating cycle (of course you need to drive one or more sound modules like NNXT etc with the matrix outputs to be able to hear anything...)
Start by making a Combinator...
Inside the combinator, create 3 matrix sequencers.
Wire Curve CV output from each Matrix Rotary inputs 1,2,3 on the combinator. Ensure these are only connections between matrixes (-ices?) and combinator
Click the "show programmer" button. Click on Matrix 1 and next to "Rotary 2" source select "Pattern Select" target. For Matrix 2 map Rotary 3 to pattern select, For Matrix 3 map Rotary 1 to pattern select
Flip to Curve view on each matrix and draw a few random curves (Randomize pattern option can be good). Start the Matrixes and click randomly on their pattern screens. Soon they should be flicking between patterns almost at random
Wire the Gate and Note CV outputs of one or more matrix to a sound module such as NNXT. 
Flip the matrixes to note mode and click at random on the screens. Change pattern lengths and note resolutions, try the "randomize pattern" option. After a while things should be getting pretty freaked out
