Not something borrowed this time, but an original.
I'm not sure when I've written this, but it is many years ago already.
Recently rediscovered and modified a bit to my current standards.
Also introduced UTF-8 style bars, so the precision has increased a bit over the old 3-level circles.
It will draw a graph based on data from stdin. First value will be the height of the graph, the rest of the values the data.
i.e.: graph 10 0 1 2 3 4 5 6 7 8 9
Here's a static image of some random data from graphtest.sh:
