http://feephome.no-ip.org/~feep/factoprod/
You can click on target items and it'll show you the requirements to create them in a graph, left to right. Select multiple target items and get a combined graph.
This might be useful for planning assembling machine layouts.
Graphs are largely based on sparr's tools (Thank you!): https://github.com/sparr/factorio-data-extract
Simple example:
Enjoy!