This block should have a 'front' and 'up' direction, be contained in a node, and while it's in that node, changes the node's out edge in the 'front' direction to instead point to the node at the 'front, right'.
N1
N2
N3
N4
Photons originally travel out of N3 to N1. Put a magnifying glass at N3, and now they'll go from N3 to N2.
This is called a magnifying glass because you can put a bunch of them together to make a magnifying glass (or a telescope!)
Photons originally travel out of N3 to N1. Put a magnifying glass at N3, and now they'll go from N3 to N2.
This is called a magnifying glass because you can put a bunch of them together to make a magnifying glass (or a telescope!)