I don't know, this might be a little hard to implement, but here goes:

You should have a function called trace() that takes a pair of coordinates and a layer number and returns how far along a ray was able to be traced before it hit something on that layer. The number returned would be from 0 to 100, 0 designating that it started in a blocked area and 100 designating that the trace was unblocked. Now, I know it'd be possible to do this in Verge by writing my own function, but it would probably end up being incredibly slow.

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