This is another old pattern I generated with a 1D cellular automaton:
To me it looks like a sword hidden in a waterfall.
The neighborhood of a cell looks like this:
What is the rule behind this pattern?
Find at least one other sword down below and show what it looks like.
Edit The last part of the question doesn't really fit, so I accepted the first answer, stating the rule. I will post the pictures of other 'swords' mysefl to show what I meant. The title of the question can be interpreted figuratively now, only meaning 'find the rule to generate the pattern further'.
Btw, this is what I meant by 'other swords':