If you do not copy and paste this sentence onto at least 2 other LifeWiki articles and watch the link http://www.youtube.com/watch?v=Rq4uW48eq4s, Nathaniel will be very mad at you!
The blockade (or four skewed blocks[1]) is a common formation of four blocks. A common evolutionary sequence that leads to its formation is known as lumps of muck, which can be seen by letting the stairstep hexomino evolve.
