For example when I visualize Tor I change between easier to visualize 2d models and sometimes 3d models. Basically a bunch of squares with lines connecting them, but sometimes semi-transparent 3d cubes one in front of the other, from an angle, with telescoping tunnels connecting them and passing through them, to visualize the layer encrypted circuit going through the nodes. Then I imagine a stream of rectangular packets going through the tunnels and that represents the clients data. I can think of a water marking attack just by imaging the packets being modified to have a unique spacing pattern between them, and I then see that this spacing pattern continues with the entire flow of the traffic after it is inserted. When I think of Freenet I imagine a bunch of cubes in a grid shape, with one on top of the other, and a bunch of tunnels connecting to them. Then I picture data flowing through the nodes as before, but now it goes through a lot of nodes instead of through three, and the tunnels are not layered.