It is sometimes possible to walk between two connected storage tanks as in the picture below
To reproduce this reliably, place 3 of the 4 storage tanks of the 2x2 grida as above. Now try walking to that inner corner. Sometimes you walk through (usually vertically, occasionally horizontally). Then you can place the 4th tank and still get out. If you don't change your perpendicular position, you can run other parallel storage tanks connections.
This doesn't feel intended. However if could do this reliably, one could setup storage tank run through zones.
Initially I thought the tanks were not connected. However they were indeed connected.